There isn't. It is planned to add an algorithm for grouping tabs into processes and dynamically adding/removing content processes, but that's low priority right now, because the current focus lies on getting the single content process e10s ready for the release channel.

More info in the e10s-multi bug and its dependencies:

https://bugzilla.mozilla.org/showdependencytree.cgi?id=e10s-...

(also a nice way to look for known issues that might affect you if you're interested in trying out e10s-multi)