IMO, the girls was just as close as the guys, but they just didn't show it so much... You can only see them showing that on a few episodes, like the one when Rachel "finds out" about Chandler and Monica, and she was upset because Monica was hiding that from her... Or when Rachel thinks Julie's stealing Monica from her... Or when they read that book with the goddesses thing you know...
And I think they fought just as the girls did. It's just that the girls are more dramatic... idk.
But obviously, none of them were more closer than Chandler and Joey, that's for sure hehe