Assign static reservation to a different subnet

[mudmanc4]

I've been staging boxes from one subnet, where I would like to assign them reservations on another subnet, where they will eventually live. This is not permitted by default.
It's not imperative that this can be done, just now becoming an inconvenience as I further segregate networks while expanding.

Example, I work from 10.0.x.x
The machine I build will eventually live on 10.1.x.x

Thoughts or ideas ?