2004 F150 - Dual rear view cameras with headunit

Hi, I have the following equipment that I need to figure out how to install, as a newby but fairly technically competent user...

• Headunit: Pioneer AVH-3600BHS
• Camera 1: Rear View Safety RVS-771
• Camera 2: Rear View Safety RVS-MV1
• Switch: Rear View Safety RVS-501N-3
• 12m 5-pin cable (RVS camera 1 to switch) installed
• 12m 5-pin cable + 12m extension (RVS Camera 2 to switch)
• Wire to tail light for trigger (installed)

The RVS-501N-3 switch has 3 wires, one for each camera, as well as one wire for ground, one wire for power, and one wire for the trigger. I know the trigger goes to the headunit and the power goes to a power source (cigarette lighter wiring) and the ground to a ground wire (??). What I don't know is what to do with each of the wires labeled for each camera. I assume they are trigger wires and need to be connected to some switch, but I don't know what... The headunit obviously doesn't have that functionality, so I need to find a way to fab a switch of sorts. They're a single wire, not paired wires, so I have no way to create a circuit... I don't know what kind of switch I'd need to buy, I was thinking some sort of momentary or toggle switch, but couldn't make heads or tails of how to wire it... I'd think a selector switch with options for 1, 2, or 3 would be ideal and I could find somewhere close to mount it, but I need to know what switch to buy and how to wire it. Does anyone have any input on how to do this project? I've also attached a drawing I've done of the rough way the wires are set up... Thanks!

Truck is a crew cab 2004 Ford F150, if that is necessary...

4 position (off + 1 2 3) switch that I think might work? http://www./itm/660V-20A-6-Terminals-4-Positions-Rotary-Cam-Changeover-Switch-New/351564685494?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20131003132420%26meid%3D1890cfd0e28e4b128bb5f95996ca499e%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D181992230955

Corrected link... Please ignore the above link atrocity... I didn't know it'd get truncated and unusable (and can't edit)...

Ug... Sorry again, someone delete those? Ebay link won't work, try searching this? "660V 20A 6 Terminals 4 Positions Rotary Cam Changeover Switch"