Jen, wish I could come up with something for you!!
Guy and Girl thing can be tuff as what to do for each one.
There was a Greater KC LXA Alum thing that did not work out so we did our own Chapter thing!
Finding thing for women to do to show up, well I am a little out of practice on that
How about a Victoria Secret Party
It is tuff to get the line broken to get a few certain people to attend and to let others know what you as an Alum Group are doing

A line of Coummunication such as a email address book just to let Alums know what if Happening might be a start! Mention Names and Chapters of members who are with you!
Bullshit can go a long way as if not there, who is to say it did not turn out so good!