You are there really, just disable conversation propagation when changing between conversations.
I'd appreciate a working example. Adding <f:param name="conversationPropagation" value="none"/> to my link resulted in no end of different troubles, and I gave up when getting a null pointer clicking the view mode link after initiating an edit mode sequence, where the Seam Blackbox is for some unfathomable reason trying to render components on a page I'm not even trying to navigate to.
Seam is like great drugs with terrible aftereffects. It's totally awesome, but you never know how you're going to feel the next day.