diff --git a/src/ai/api/ai_grouplist.cpp b/src/ai/api/ai_grouplist.cpp
new file mode 100644
--- /dev/null
+++ b/src/ai/api/ai_grouplist.cpp
@@ -0,0 +1,16 @@
+/* $Id$ */
+
+/** @file ai_grouplist.cpp Implementation of AIGroupList and friends. */
+
+#include "ai_grouplist.hpp"
+#include "../../openttd.h"
+#include "../../company_func.h"
+#include "../../group.h"
+
+AIGroupList::AIGroupList()
+{
+	Group *g;
+	FOR_ALL_GROUPS(g) {
+		if (g->owner == _current_company) this->AddItem(g->index);
+	}
+}