I know I cannot make adults like each other, but how can I get family together to at least be together?

[Alcoholic Researcher]

My mother and her brothers have some friction and so it is all "well we can't ask him because his parents will come" and so I miss out on seeing my cousins more then once a year and they miss out on seeing me. We are of all age groups so it is not like we would be going to movies and such as I am a lot older, but I want to get to know them. I feel bad that my grandparents' generation was close and now my mother and her siblings can't really get along and seem to tolerate each other at a distance and that's all.

What kind of gatherings could I make as someone who only lives in an apartment (would have to do it elsewhere) so the family could see each other two or three times a year (we all live 20 minutes apart). We see each other at my grandmother's birthday in October but usually don't at the holidays other then seeing my grandmother. I run into the adults at events but the 14 cousins usually only see me in October and sometimes at weddings or funerals (more often funerals).

I really like the family and want to be involved but don't want to impose on people. Any ideas? It's not like people are refusing to speak (though my mother refuses to sometimes) but just that tension with my mother has led to people not being real interacted.
These issues originated with my mother's father, my grandfather, being an alcoholic. He was a wonderful man so I remember him fondly (he died 4 years ago) but my mother developed distrust as the only daughter and was the only one to pull away for about 5 years before rejoining.