Buddypress, how to separate membergroups

Hi all,

I´ll to creat a free comunity for singles there they can contact each other. I´ll install any fixed groups like: “singles Madrid”, “singles Barcelona”, etc. for the different territories and later the members can creat also own groups.
I think it´s important that the girls only can view the “boy site” and the boys only can see the “girl site”. Because a boy that search a girl doesn´t will see other boys and in the worst case find his neighbor or brother there… :).

How i can avoid that?

Wp: 3.5.2
Bp: 1.7.2
http://www.speed-dating.es

Thanks,