What's the best way to restrict an environment to a specific CDN?

We have had problems a couple times now where the links to the CDN in our components don't get properly updated between the team, QA, and staging environments.

Is there a way to force an error if the QA environment tries to access the team CDN or vice-versa? Or some other well-known solution to this problem?

If the different CDNs are hosted at different IP addresses one possibility might be to configure the local hosts table for the machines in a certain environment in such way as to overwrite the DNS resolution for the CDNs which shouldn't be accessible and pointing them to either: