When someone clicks to create a card through a Pointer with +*options of, say, {"type": ["in", "User", "Organization"]}, offer a cardtype menu which lists only User and Organization.
If they only have permission to create one of the multiple types specified, then don't have a menu, make the new card that type. (If they don't have permission for any of them, then of course show the you-must-sign-in-to-edit stuff.)
What's the inclusion syntax? Can't be {{foo+uploads|type:Image,File}} because we allow commas in card names. How about {{foo+uploads|type:Image/File}} ?
