This may require some hard studying of the ToS and methods to approach hosting since there are always two parties involved in multiplayer games: The host and the client. We'd first have to clarify which method of 3rd party multiplayer is acceptable to Rockstar/TakeTwo, if any at all, or to see if there's at least a way around their idea of multiplayer that doesn't violate the terms of service. But do you think you could be able to develop lspdfr for this mod?
I said, for now is a posibility, is better than nothing, wait for Rockstar and Take2.