Heidi & Audrina Hang...So Who's Out With L.C.?

Lauren has lunch with Heidi's sister over the weekend while the Hills villain parties with L.C.'s roommate

Just because Audrina Patridge lives with Lauren Conrad doesn't mean she can't party with Heidi Montag.

Both girls were filming The Hills Friday night at the T-Mobile Sidekick LX Tony Hawk Edition launch party with their respective boy-toys in tow.

An eyewitness reports that the entire group, including Spencer Pratt and Justin Bobby, seemed to be "in good spirits and getting along."

So who was left to pal around with Lauren?

In a twist reminiscent of L.C. coincidentally befriending Stephanie Pratt last season, Lauren was spotted lunching this weekend with Heidi's sis, Holly Montag.

The two blondes dined outside at Amadine Café in Santa Monica, conveniently in full view of photographers.

So let's recap: Lauren hates Heidi and Spencer, but she can be friends with their respective siblings?

Sounds sort of hypocritical to us...what do you think? Sound off in the comments section.