Where to start 1st you would need 2 different builds of LB and then if you wanted to use all the same media you would have to take your 2nd instance and edit all the folder paths for each individual platform to point to the location of the 1st instance and then use some type of sync software to like your data folder for both installs. You could also do the same thing but use simlinks for your image, music, manuals and videos folders and then they would both have the same media. For the emulators and ROMs you would want to keep them outside of LB and just point both installs to the same rom and emulator paths.