Got it working, a few tips for anyone trying to do something alike.
first read the official info: https://docs.unrealengine.com/latest/INT/Engine/LevelStreaming/WorldBrowser/index.html
1.- have two or more levels
2.- make another (the simple transitional one) make it persistent by checking enable world composition int “world settings” tab
3.- create a new layer in the world composition window at that moment disable streaming distance
4.- move the levels but the persistent one to the new layer (right click on the level browser and assign to layer)
5.- then you can test by load and unload them in the level blue print of the persistent one
How communicate from the normal levels with the persistent one in order to load and unload persistent or switch game modes I still dont know, tomorrow Im going to keep on testing…