Network coupler for Gas or Moist Air domain doesn't exist as of R2024b.
I see two options:
(1) follow the structure of such component for the TL domain, and write your own coupler for the Gas domain. The key component is the "partialChamber". You may compare it to the regular constant volume chamber and understand the type of change needed to be made for the Gas domain.
(2) ask yourself whether the original model has been optimized numerically and whether splitting it is the only path forward. More details, e.g. an attached model, will help clarify on this.
