Combine channels to custom services
I am using a HM-LC-Sw4-PCB to toggle my garage door. A key press either closes or opens the garage door. The garage door itself knows 4 states, in where it cycles: (1) Motor Upwards -> (2) Stop -> (3) Motor Downwards -> (4) Stop -> (1) ...

I that channel is exposed to homebridge-homematic as a switch, it is displayed as light bulb. 

I am using HM-Sec-SC to detect if the garage door is closed. This is exposed to homebridge-homematic as blind service, at least it displays when the door is opened.

I now want to combine these two channels into a single HomeKit device. I am thinking a scenario where a press to the icon in HomeKit would trigger the motor across the states and the icon displays if the door is opened or closed. I was wondering if "Custom Service Class" would be an approach to get this solved. If not, is there any other way to get these combined?