I got it working as 2 devices.
I used @ericm device driver for the Monoprice 11990 Dual Relay. Play with the On1, Off1, On2, Off2 buttons to see which relays/physical devices those control.
Monoprice 11990 Dual Relay device driver
I then used @bertabcd1234 Virtual Switch: State Change device driver to create 2 virtual switch devices for each physical device controlled by the relays. This virtual switch driver sends the state change command no matter what.
Easily Change Virtual to Group? - Get Started / Novice Help - Hubitat
Then need to create 4 Rules Machine rules: an On and Off rule for each device.
The Trigger event will be the virtual device switch turning On (or Off).
For the Action select Set Mode, Variables or File, Run Custom Action, then select Run Custom Action.
For the capability, select Switch, then select your Monoprice Relay device.
Then select either On1 or On2 for the custom command depending on which relay/device you want to control.
Repeat these steps to create the Off Rule for this device.
Repeat those steps again for the 2nd device.
You can then use these virtual devices with your Apps including Alexa to turn them On or Off as expected. The only issue is that current state of the virtual switch may not match the actual state of the physical device. However no matter what, when you or an app tries to turn on the device using the virtual device it will turn it on even if it thinks it is already on.
