Yes, it's possible to make new teleporters. Basically, you have to place an 'event' on the object you want to click on, and then define that event. I can't give you precise details on how to do that without digging back in the files. I believe the newest version of the MM8 editor gives you the ability to edit some event types, but I don't think it allows you to add any. Some hex editing might be involved. Even when you click on a door, however, an event occurs. For example, clicking on the 'door' to a dungeon actually teleports you to a location in that dungeon. So I believe you could change the event for an existing (but fairly useless) door, for example and make it into a teleporter.
