RebE, yes, some teich people to follow minhag of the one who asked: “we do this, and you do this”. I am very comfortable asking such Rabbis shailohs, as I know they’ll answer according to the one who is asking. See example of R Feinstein advising someone to follow person’s Rebbe, r Soloveichik, on an issue, on which r Feinstein just signed a public letter opposing that position.
The other shita – everyone has its gate, but their gate is bigger than other gates and open to everyone, is more problematic, as when many groups start claiming their gates … I am not even sure whether this shita has a history in Gemora or Rishonim, or should be considered a modernishe one.