Group Activated Phantom Door

Very simple. Just a translucent prim. Rez it, set the group you wish, if anyone is within 5m of the object with the right group tag on, the prim will become phantom, allowing the avatar to pass through it.

Full permissions, edit it however you please, give it to a friend, do as you wish. The script is also full permissions so you can easily change the range etc.

Note don't Ctrl+L link it to your house or the whole building will become phantom.