Im not sure if its possible, but.. Well lets separate W:A to laucher and game. Laucher its kind of game set up, those menu, lobby, server and setting. Game its game from it start and till end.
There is option for scheme that can keep weapons from last rounds and move them to next (used on pro, kaos), While all those weapons setting transform from one round to another they will stuck on lobby, so they obviously saved somewhere maybe on ram or just in game folder or wherever it can be. This means if both players change weapons setting the same way via hex editor (if its somewhere on ram) or maybe some file (if setting is out of exe) on lobby between rounds and only with scheme where weapons moves between them you can put any weaps with opponent you need
I wonder if its possible and still its pretty hard to set up but LOL, you can continue games like t17 after drop!! You just was too nooby to do that!