Is it possible to follow the railroad quest until the end to when a nuclear option starts / would start, then go to the institute kill someone, get banished and follow/end the game with the minutemen questline (defend the castle etc.)?

Or do you get locked out from the m-m ending when you tell them to stay down (not kill them) during pinned?

or when is the last option to switch to the minutemen ending? cause i want that and defend the castle, but i think the lead up is rather weak and much more interesting for the railroad especially for destroying the bos...also i think its kinda the coolest ending to play bos/institute until the very end, kill father personally (as it should be) and then lead the minutemen to freedom and victory...