[Feature Request] Option to Combine Two Plug-ins in a Child Bridge
### Current Situation

Currently I have what I will call a 'sudo-plugin' that piggy backs off another plug-in. My plug-in essentially provides a shell script to this other plug-in which does all the Homebridge heavy lifting. My plug-in is Homebridge verified and integrated in Homebridge UI as a delivery method of keeping the shell script up to date for my user base. That being said, my plug-in cannot run without the other one and I would like a method to combine the two plug-ins as a child bridge; which I believe is currently not possible.

### Proposed Change

Create the option to be able to combine child bridges. 

### Additional Context

My [plug-in](https://github.com/mitch7391/homebridge-cmd4-AdvantageAir) and the [plug-in](https://github.com/ztalbot2000/homebridge-cmd4) it piggy backs off might be a unique situation, but I could see how it could be useful for users who would like to combine two similar themed plug-ins into a child bridge.