Season four episode Saving Private Leo, the actor playing Rick was Costas Mandylor who has worked with Shannen and Holly in other projects.
He was in Picket Fences with Holly (so it wouldn't surprise me if she put in a good word for him) and he was in Almost Dead with Shannen in 1994.
The actor that played Rick's brother is Costas brother.
*hugs*
xoxoxo