I'll probably get grilled for this, but if the university knows they're there and IF (that's a big IF) the national groups would like to re-esatablish a chapter, why would the university not try to allow the recolonization the chapters. The university could reign them in at that point, institute the appropriate rules and the national orgs could enforce (sp) their policies.
I mean if they are already recruiting, then why not just make it official and save all the heartache. Then again I sometimes live in a dream world and this could be completely impossible!
