AWS CDK: Add new stack to my IAC, or create a new IAC?

I have the next infrastructure

One IAC done with aws cdk with python that deploys mi main app microservices, this IAC also creates the cognito user pool and deploys my frontend app.

Now, I've developed a new part of the app that consist on another set of microservices. One of this new set of microservices will need at least access to the cognito user pool, and the frontend of my main app that is in the IAC will need access to some variables of the new set of microservices, but about functionality it is a sepparate functionality from the main app. Should I create another IAC to deploy this new set? Or should I put it inside the IAC I already have working?

Thank you!