LTR keeps inviting me to dinner or drinks with her friends. I don't really want to go because they all know each other so I will not understand most of the conversation. However, I do have a somewhat limited obligation to get to know her friends a little bit and be nice to them.

I have met her friends in passing and do not find them interesting enough to enjoy dinner with. They are nice people but would annoy me if I had to hang out with them for more than ten minutes.

Where is the line between being polite to her friends and enforcing my boundaries of not hating having to force small talk with her friends?

TLDR: LTR wants me to get dinner with her and her friends, I don't want to, but recognize need to be kind and friendly to her friends. What to do?

Looking for actual insightful comments on social mores as opposed to random sidebar quotes that are inapplicable, thanks in advance