Change assets dir or load assets from other dir to default dir at runtime

I have 3 different android builds(exported from Unity 3D); I want to trigger them from a single android app. Unity 3D creates a single asset archive and splits them into 1MB files (.split(n)); i cannot combine all assets in the data directory as they get over written and there is no way to determine which file contains what asset.

So I have created 3 folders in data viz. 1,2,3 and would like to load the assets from these directories at runtime (onClick).

Also tried asset bundles, but the problem persists when dealing with multiple android builds...

I would like to know if there is a way of doing this or is there another solution for this problem ?

Thanks.

http://i.stack.imgur.com/Ah7DO.png