On our campus we recently changed the rules because it basically consisted of almost three months of "let's avoid all rho gammas and pi chis".
Now we have something called Positive Panhellenic Contact. We talk, we laugh, in and out of our letters on campus, but we do not discuss recruitment/PNMs/anything negative or rude, etc.
We don't go out (off campus) together with letters or whatever but we can go out until the Rho Gammas receive their list of women and after that point it's strict silence. You still can't say "See you tomorrow!" to a PNM after a party or ask where she's attending that night.
I pretty much hated the rules and did my own version of Positive Pan. Contact because PNMs were getting creeped out. We looked like a bunch of frigid bitches that hated each other all summer before. You'd see people running past their Rho Gammas with eyes averted because they were afraid to even look at each other. (Can you make it more obvious?

). I have no problem walking, hugging/kissing/greeting any sorority woman I know because not only are they my constituents, they are my friends. And if some PNM decides that she's certain I'm an XYZ or whatever because she saw me talking to one and then that's what she wants to be, then so be it~hope she has fun on bid day!