Remote locking kit - Window roll-up feature

[Sala296]

Hi there, 

So I got a remote central locking kit for my 2000 Yaris. I've got the majority of it hooked up, and it works fine as is. It has a wire that grounds for 30s to close the windows for you when you lock the car. It would be so handy, because almost everyday I switch the car off, open the door and notice the windows are down haha. Anyways, I've not tackled this one yet, as there are 2 windows but only one wire. Of course, if I split the wire to both windows, it will lead to both windows being synced. If I open one window the common ground wire will make the other open too. The only solution that has come to mind, is the use of diodes, however I can't seem to find any that are rated to handle the 15-20A or so that would be needed.

Is there either 1). An alternative way to wire this, or 2). A diode that can be used for this case?

Many thanks, Michael.