You may be able to contact the creator for a vmf, or hunting for the bsp, decompiling it, and getting the vmf. From there, you could add the multiplayer entities to the map and play it like a multiplayer.
You may be able to contact the creator for a vmf, or hunting for the bsp, decompiling it, and getting the vmf. From there, you could add the multiplayer entities to the map and play it like a multiplayer.