So, I'm gonna do another play through working for Mr. House, I know he askes you to kill the BoS, but I just don't want to. They are one of my favorite groups in Fallout and although I don't have a problem playing an evil character, I like "lawful evil" in that, its kinda dike and backstabbing to kill them after they have taken me in and given me power armor training etc. I have no problem killing people I havn't already made alliances with. Anyone know if you can work for Mr. House and not kill them, or is it unavoidable?

They are a threat to Mr. House, he won't let them live. The biggest threat in fact. Mr. House is specifically the kind of thing the Brotherhood vow to prevent.