Try this:
map.connect 'admin/:controller/:action/:id'
map.connect ':team_name/:action/:id', :controller => "siteview"
1) The Route for the admin part has to be before the other map in the routes file, otherwise the other route would match also for /admin/... and look for a team called "admin" (btw: you should prevent creation of a team called "admin" as that would never be able tothe public views...)
2) you have to specify the controller for the :team_name route ...
Hope that helps, maybe you could give more info if not...