Two Apple Watch Companion Targets possible?

Question

What I have

I have a WatchOS companion app that has a deployment target of 4.0 or later. It is written in WatchKit and UIKit (?).

What I want to do

I want to update the WatchOS companion with the new WatchOS 10 features and write it in SwiftUI. However, I still want WatchOS 9 or earlier to have access to what I mentioned above.

Is this possible?