diff --git a/openrct2.vcxproj b/openrct2.vcxproj
index 9615badaff..5952fcceda 100644
--- a/openrct2.vcxproj
+++ b/openrct2.vcxproj
@@ -314,6 +314,7 @@
     <ClInclude Include="src\core\List.hpp" />
     <ClInclude Include="src\core\Math.hpp" />
     <ClInclude Include="src\core\Memory.hpp" />
+    <ClInclude Include="src\core\Nullable.hpp" />
     <ClInclude Include="src\core\Path.hpp" />
     <ClInclude Include="src\core\stopwatch.h" />
     <ClInclude Include="src\core\Stopwatch.hpp" />
diff --git a/src/core/Nullable.hpp b/src/core/Nullable.hpp
new file mode 100644
index 0000000000..37e3393cfe
--- /dev/null
+++ b/src/core/Nullable.hpp
@@ -0,0 +1,55 @@
+#pragma region Copyright (c) 2014-2016 OpenRCT2 Developers
+/*****************************************************************************
+ * OpenRCT2, an open source clone of Roller Coaster Tycoon 2.
+ *
+ * OpenRCT2 is the work of many authors, a full list can be found in contributors.md
+ * For more information, visit https://github.com/OpenRCT2/OpenRCT2
+ *
+ * OpenRCT2 is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * A full copy of the GNU General Public License can be found in licence.txt
+ *****************************************************************************/
+#pragma endregion
+
+#pragma once
+
+#include "../common.h"
+
+template<typename T>
+struct Nullable
+{
+public:
+    Nullable()
+    {
+        _value = T();
+        _hasValue = false;
+    }
+
+    Nullable(const T &value)
+    {
+        _value = value;
+        _hasValue = true;
+    }
+
+    bool HasValue() const
+    {
+        return _hasValue;
+    }
+
+    T GetValue() const
+    {
+        return _value;
+    }
+
+    T GetValueOrDefault(T defaultValue) const
+    {
+        return _hasValue ? _value : defaultValue;
+    }
+
+private:
+    T       _value;
+    bool    _hasValue;
+};
diff --git a/src/network/network.cpp b/src/network/network.cpp
index d7b2f839d3..e77556cada 100644
--- a/src/network/network.cpp
+++ b/src/network/network.cpp
@@ -1318,7 +1318,8 @@ uint8 Network::GetGroupIDByHash(const std::string &keyhash)
 {
 	auto it = key_group_map.find(keyhash);
 	if (it != key_group_map.end()) {
-		return it->second.GroupId;
+		auto groupId = it->second.GroupId;
+		return groupId.GetValueOrDefault(GetDefaultGroup());
 	} else {
 		return GetDefaultGroup();
 	}
@@ -1429,7 +1430,15 @@ void Network::SaveKeyMappings()
 		for (auto it = key_group_map.cbegin(); it != key_group_map.cend(); it++) {
 			json_t *keyMapping = json_object();
 			json_object_set_new(keyMapping, "hash", json_string(it->first.c_str()));
-			json_object_set_new(keyMapping, "groupId", json_integer(it->second.GroupId));
+
+			json_t *jsonGroupId;
+			if (it->second.GroupId.HasValue()) {
+				jsonGroupId = json_integer(it->second.GroupId.GetValue());
+			} else {
+				jsonGroupId = json_null();
+			}
+			json_object_set_new(keyMapping, "groupId", jsonGroupId);
+
 			json_array_append_new(jsonKeyMappings, keyMapping);
 		}
 		bool result;
@@ -1466,11 +1475,14 @@ void Network::LoadKeyMappings()
 		
 		const char *hash = json_string_value(json_object_get(jsonKeyMapping, "hash"));
 		const char *name = json_string_value(json_object_get(jsonKeyMapping, "name"));
+		const json_t *jsonGroupId = json_object_get(jsonKeyMapping, "groupId");
 		if (hash != nullptr && name != nullptr) {
 			KeyMapping keyMapping;
 			keyMapping.Hash = std::string(hash);
 			keyMapping.Name = std::string(name);
-			keyMapping.GroupId = (uint8)json_integer_value(json_object_get(jsonKeyMapping, "groupId"));
+			if (!json_is_null(jsonGroupId)) {
+				keyMapping.GroupId = (uint8)json_integer_value(jsonGroupId);
+			}			
 			key_group_map[keyMapping.Hash] = keyMapping;
 		}
 	}
@@ -1507,7 +1519,14 @@ void Network::UpdateKeyMappings()
 			std::string hash(json_string_value(json_object_get(jsonKeyMapping, "hash")));
 			decltype(local_key_map.begin()) it;
 			if ((it = local_key_map.find(hash)) != local_key_map.end()) {
-				json_object_set_new(jsonKeyMapping, "groupId", json_integer(it->second.GroupId));
+				json_t *jsonGroupId;
+				if (it->second.GroupId.HasValue()) {
+					jsonGroupId = json_integer(it->second.GroupId.GetValue());
+				} else {
+					jsonGroupId = json_null();
+				}
+				json_object_set_new(jsonKeyMapping, "groupId", jsonGroupId);
+
 				// remove item once it was found and set
 				local_key_map.erase(it);
 			}
@@ -1521,7 +1540,15 @@ void Network::UpdateKeyMappings()
 		json_t *keyMapping = json_object();
 		json_object_set(keyMapping, "hash", json_string(it->first.c_str()));
 		json_object_set(keyMapping, "name", json_string(it->second.Name.c_str()));
-		json_object_set(keyMapping, "groupId", json_integer(it->second.GroupId));
+
+		json_t *jsonGroupId;
+		if (it->second.GroupId.HasValue()) {
+			jsonGroupId = json_integer(it->second.GroupId.GetValue());
+		} else {
+			jsonGroupId = json_null();
+		}
+		json_object_set(keyMapping, "groupId", jsonGroupId);
+
 		json_array_append(jsonKeyMappings, keyMapping);
 	}
 
@@ -1946,7 +1973,7 @@ NetworkPlayer* Network::AddPlayer(const utf8 *name, const std::string &keyhash)
 				player->SetName(MakePlayerNameUnique(std::string(name)));
 			}
 		} else {
-			player->group = keyMapping->GroupId;
+			player->group = keyMapping->GroupId.GetValueOrDefault(GetDefaultGroup());
 			player->SetName(keyMapping->Name);
 		}
 
diff --git a/src/network/network.h b/src/network/network.h
index 7bf71b183f..b19c27553d 100644
--- a/src/network/network.h
+++ b/src/network/network.h
@@ -121,6 +121,7 @@ extern "C" {
 #include <map>
 #include <SDL.h>
 #include "../core/Json.hpp"
+#include "../core/Nullable.hpp"
 #include "NetworkKey.h"
 
 template <std::size_t size>
@@ -340,9 +341,9 @@ private:
 };
 
 struct KeyMapping {
-	std::string		Hash;
-	std::string		Name;
-	uint8			GroupId;
+	std::string			Hash;
+	std::string			Name;
+	Nullable<uint8>		GroupId;
 };
 
 class Network