Ignoring someone leads up to cutting all the possible routes that may be connected from there, and although you think that you are revenging others by doing that, what it all does is simply torturing yourself and putting yourself in a detrimental position.
what to do then?
Forget about it. (preferably don't even let it bother you at the first place)
If can't, then you should still maintain the relationship, and preferably still be nice disregarding whether you like it or not. Because things may change, so you don't want to break a connection so easily. Moreover, because you don't want to break the connection from there.
Maybe adding in some communication would help, if appropriate.
One's life and social cycle revolve around one's self; so being affected negatively would only lead to undesirable consequence for oneself.