Hi, Larry-
I am afraid I don't see how that could be accomplished. Perhaps something involving huge amounts of Monte Carlo simulations/bootstrapping, but it seems hard to get an objective answer to that question that wouldn't be highly assumption- or model-dependent, as well as one that would generalize.
Is there a way that you can reformulate that question of interest into something that would fit into a statistical test framework more directly? Can you not analyze those groups in a single test, say?
--pt