I became friends with a circle of people because we share a common interest. We meet for dinner perhaps once a month and our conversation mostly concerns our shared interest. We are not really involved in each other's personal lives. With fall coming up, they are making plans for us to do a lot of things (related to our "hobby"), but I don't think I'll have time to join them because the wedding is in October. I feel odd telling them the reason why I probably won't be very available in the next 8 weeks, given that they are not invited.
I have become friends with one woman in the group, but we're still not really close friends, so it never occurred to me to invite her to the wedding. Is it rude to mention one's wedding to acquaintances or co-workers who are not invited? I assume that they wouldn't
expect to be invited, but who knows?