1. Place an Independent unit (as player) in the editor.
2. Place a BLUFOR or OPFOR unit (as AI) in the editor and name him Unit1
3. Run command:
Call Compile Format ["GRP = CreateGroup %1", Side Player] // GRP = CreateGroup GUER
GRP will be nil.
4. Run command for the AI unit:
Call Compile Format ["GRP = CreateGroup %1", (Side Unit1)] // GRP = CreateGroup WEST/EAST
GRP will be created.