Hello,
This scenario is coming up often now.
Cloud manager allows multiple code quality pipelines but only one deployment pipeline which promotes the code till prod deployment with several steps including checks and approvals from CSE.
I think two options are there with a bit of restrictions and varying degree of effort:
1. Create separate branches (you can call them long running feature branches) and map them to the deployment pipeline when required. You can keep promoting or cancel the pipeline in dev or stage to allow other pipe lines to be allowed for deployment. It assumes you have a good gatekeeper and good quality control practices so that one site does not write/update others etc. This is simple to do but has a lot of operational effort and involvement of cloudmanager gatekeeper.
2. Have a local master repo where the local repos can sync the codebases. Once deployment to AMS environment is needed, you need to sync it to cloud manager git using jenkins hooks. So ideally use cloudmanager as code promotion for QA, UAT only on need basis and not a day to day code push. This solution will work but need effort in terms of setting up some infra and processes initially.
Thanks!