FRsky bind 2 RXs to 1 TX

[jwwrunner]

I have successfully bound (binded) a BetaFPV 65s mini quad (F4 Brushed FC with built in FRsky Rx) to my FRsky QX7. I am working with my students on a project and would like to bind an additional RX to the QX7 to operate an independent servo. Essentially the RPIC flying the Beta 65s is operating the QX7 and is able to hit a switch on that same radio to open a door (simple servo) for the drone to fly into a storage unit. I have a variety of RX's to work with if a special one is required. FRsky RX4R or XSR. There are brief videos online about binding the 8XR and 6XR simultaneously, but I am wondering if it is limited to those two only? I am not looking for redundancy either. Any help to walk me through for an intermediate user would be a great help. Thanks. Here are the current settings on my QX7 TX for the 65s mini quad

Internal RF
Mode. D8
Ch Range Ch1-8

 

[FDS]

I think you will struggle to do that with a pre built SPI receiver, I think the receivers needed to be linked by Sbus. I would just have a bell push and wire for the door, operating a servo via a driver board, easier and cheaper.