Windlass & bow thruster remote

[Foozinator]

I'm looking at replacing our foot switches for the windlass with a handheld unit. I see these (http://www.quickusastore.com/hand-held-remote-control.html) come in a 4-button version. Having control of the bow thruster up at the bow could be handy when approaching a mooring ball.

What I'm not sure about is the best way to wire up both motors when all 4 switches have a common wire. Does anyone have any recommendations for a double-throw relay or something else for isolation?