pre-scene to load asset bundle

Our team already have a workable unity3d game project which deploy to android and iOS without problem and work fine. Recently, I receive a request to write a "welcome" scene which shows a welcome artwork and detect any new version is available. If new version is found, it will download all other existing "real" scenes and corresponding assets, prefabs, texture .... from our server. If all loaded successful, it will switch the control to the loaded game scenes. That is all what the "welcome" scene does.

I would like to ask whether it is possible to include the current game project (scene + asset + prefab + ...) into an asset bundle without modifying the codes? My boss is asking whether we could create another project for the special "welcome" scene, without affecting the current game project and scenes. I am now figuring out the feasibility of this approach.

Anyone have experiences on this? Appreciate your help.