Hearthfire

Hello there! I've been working on a multiplayer map for Tiberian Sun. My goal is to give an AI a base wich 1-X players can destroy together. Something like a coop-thing, you know? Nothing special in my eyes. I tested it with a few buildings. When i give these buildings to an AI it immediately sells everything except a construction yard or buildings the AI is not able to sell. Maybe it's a dumb question, maybe it's already answered by someone (then I'm sorry that I'm unfit to do a correct search...). I was searching for a solution but couldn't find anything about that. Is it even possible to realize this? Can I reject the AI to sell the given buildings? If it's not possible that way, is there another option to realize this project? Thanks in advance for your help.