Well.... I have an Andromada script, I am a moderator on a server, that has an andromada script, you can open the back door, and cars can come inside, I can give it to you.
Edit: Not to you, to MTA development.
Well I can get a shot at it. I am not PRO, I am good but not PRO. I can help with some stuff, sure for free. But I can't do everything alone, I will need another scripter with me.
Forgot to mention, this script will allow cars going inside the andromada by it's door (BACK DOOR) it has no interior, it can easily be made, but I don't know how!.