One mother at my mothers group used to continually exclude me from her kids birthday parties, and when she and a few others started up a new play group I was excluded from that too.
I found out later that she used to think I was a stuck up snob all because of how I speak, and because I was a quiet person.
I hate bullying of any sort with a passion, I was bullied all throughout high school and it wasn't nice.
My sons only got 6 kids in his class at school (he goes to a school with a special needs unit) and if he was to have a birthday party, then I wouldn't exclude any of them as it's not right, and they are all of his friends.
Oh well I never was there ever a cat so clever, as magical Mr Mistofolees!