None of this is possible at the moment, you would have to use custom svripts and multiplayer does not allow custom scripts. The reason being is that because of the way it operates both players have to have the same media and if you use custom scripts the other players will get errors because they dont have them.
It may change in the future. But for now nothing is planned soon.
i7 7700,k NV1070 8GB, 16GB 3200mhz memory, 1x 2TB Hybrid, Win10.
i5 4760k, NV960 2GB, 16GB 2333mhz memory, 1x 2TB Hybrid, Win10.
i3, Intel 4000 series graphics, 6GB memory, 1x 500gb HDD, Win8.1.