Welcome to Microsoft Q&A Platform, thanks for posting your query here.
Based on your ask, looks like you don't want to deploy some services in a specific SF cluster. Please let me know if I am missing anything here.
However, if this is your ask, it is completely dependent on you which service/application you want to deploy and which you don't want to in SF cluster. If you don't want to deploy any service, you can remove it from you tools like Devops, visual studio , etc. and it won't get deployed.
Also regarding region specific, then Service Fabric cluster gets created in a specific region and VMSS comes handy for that, so all your apps/services will be specific to a region where SF cluster/VMSS are present.
Hope that helps.
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