It's difficult. I'm all for reporting stuff like abuse or defalcation (or whatever it is you're talking about) and clarifying things.
However you don't stand a chance if you don't have the spiritual teacher or a majority of that group on your side. If you try to expose one or all of the ingroup running the center but (1) you cannot actually prove anything and (2) the Tibetan teacher has a hands-off approach (because he thinks it's none of his business, or he doesn't want to dirty his hands with "dharma politics", or he thinks this is only a problem of your perception and you should work on your perception instead, or he just doesn't care) chances are a 99% majority of the center's members will turn against you.
They'll accuse you of negative speech, having evil intentions, splitting the Sangha, trying to badmouth the people who work so hard and relentlessly to make this wonderful place of Dharma transmission possible, not keeping the Pure View, acting out of jealousy, trying to kick the leader out because you want to be the next leader, playing power games yourself, trying to act out on someone because you have personal problems, being neurotic, disturbed or even psychotic. In the end the only thing you'll have achieved is that you'll get mobbed out of the center.
While ethically reporting the issue may be the right thing, strategically you should be careful. Try to contact the teacher first and see if he takes the issue seriously and if he's ready to concern himself with it. If he's not accessible or has a hands-off approach you can carefully put your toe in the water and check the temperature by approaching some members of that community who appear trustworthy to you and tell them about the issue in a face to face conversation. If the reactions you get are brainwashy BS answers like those I listed above it's time to realize there's nothing you can do.