Hi,
It will greatly depend on your logic implementation, wether you can "transport" player in a different location of your level, same with enemies, etc etc.
Since Unity is not a Linear system, like a video, it's hard to "fast forward" without taking this feature into account from the ground up.
If this is for test, you should be make test levels with that feature available straight away. Provided the feature is delivered as prefabs, it should be ok. I would first investigate this kind of editor only levels before messing around with affecting the whole game to test a late feature in a level.
Bye,
Jean