idea question....for possibility purposes

[ZyphonGale]

My group and I are working on a map and running into a slight problem. We are still in the design phase of it and are wondering if it is possible to make a multilayer campaign map. One of the ideas we came up with was the players can switch to a different map for a dungeon like instance and then switch back to the main map with any items they gained in that "dungeon" map. We are trying to figure out if it is possible but are not sure where to look. The answer of this question will effectively change the way we go about doing our maps so any assistance would be greatly appreciated.