I'm too the point in the main story line where

Spoiler (highlight to read):
I'm inside the Institute (I play slow, I know - I only get a few hours a week). I kept saying 'maybe' any time they ask if I'm joining them and it's becoming clear I'm going to have to choose between the institute, the railroad, and the brotherhood. I hate having to choose between different endings/story lines. Not because I disapprove of the gameplay style, it's just because I feel like I'm missing out on 2/3 of the game by only being allowed to play one. I suppose I'll have to save just before the decision and go back twice.