That's a good question. I suppose my point is that this is not something you have "fight back" against. Lots of people get excluded from social groups in professional settings due to some silly link that their coworkers have with each other.

Learning to overcome your lack of cultural commonality with coworkers and and breaking into social groups is something that all of us need to do at some point. In my case — I sucked it up, refused to learn golf but bonded with coworkers over board games; and ate the appetizers at the steakhouse.

A tip for OP would be to try doing the equivalent thing in their context. Go up to your Indian coworkers and ask if you can accompany them to the restaurant. I promise you it will be fine.