So.... Word of warning without any spoilers. It's possible to ally with more than one group in Fallout 4. I made the mistake of allying with all 4. The game gets really stupid after that. All the quests you just walk through and no one fights you except the turrets, raiders and mutants. The last quest I walked through the middle of a three way gun battle with a BoS companion and no one shot at me. I literally just walked through the middle of it, blew up two turrets and completed the quest. I tried doing anti-faction stuff to see if I could drop the relationships, but haven't been able to. They just shake their heads and say "hopefully you'll come around in time". I'm killing the game off and starting over because it's pretty worthless now. Just don't do it. Pick one or two (with common goals) factions and stick with them or just stay totally freelance.