Hmm, I'd like that as well.
Right now I use Logic Sensors, hooked up to 3 actuated tiles that act as automatic doors.
I usually use lava fall blocks, so to give a feeling that it's kind of a force field being turned off and on as the player passes through.
Added benefit: No enemy can break these 'doors' down.
Any door that isn't meant to keep out enemies (e.g. indoor doors) just remain open.