Istio setup for staging environments

Hi, does anyone have any guidance on good-practices for segregating developer staging environments including Istio?

i.e. to keep it simple, assuming a single cluster, if I had a separate namespaces for dev, integration, test (say project1-dev, project1-int, project1-test) how could istio-system be segregated to ensure istio CRDs & pods are isolated for each staging environment?

Can this be done with namespaces?

Thanks Gareth.