Ah. I figured out a solution. It's inelegant, but it'll do the trick, I think.
I'm setting up a room. Players teleport to point A.
Point A has multiple teleport points in it.
The player steps on one of the teleport points on the world map. This activates an event for that specific teleport point.
There is a matching teleport point at the tower. Stepping on this brings up a single yes/no choice asking if they wish to teleport to the teleport point in the field. It isn't active until they step on the event and activate a switch.
So the event looks like this:
Page 1:
Show Text: This needs to be activated.
Show Graphic: Inactive Magic Circle.
Page 2:
Condition: Switch "Teleport Points Can Be Activated" is on.
Show Graphic: Active Magic Circle
Show Text: This spot is now activated!
Show Choice: Would you like to teleport to Point A? Y/N?
If yes, teleport to point A.
Control Switch: Teleport Point One is activated.
Page 3:
Condition: Teleport Point One is activated.
Show Choice: Would you like to teleport to Point A? Y/N?
If yes, teleport to point A.
Control Switch: Teleport Point One is activated.
The sympathetic event at Point A's room is almost the same, but asks if you want to teleport to the teleport point in the field. It's active when the "Teleport Point One" event is activated.
This solution is still complex and a bit ungainly, but I suppose it works. If anyone can think of a better way to do it, please let me know.