Blech, I'm not a social butterfly at all, but what about just "being busy" whenever she calls.
No need to declare war but more of a "Oh I'm sorry, but we just can't do that right now..we're busy."
and just don't respond to any of their requests anymore... maybe if there is a house a fire /emergency or something like that then it would be good to check on
she'll get the hint sooner or later.