Can a different domain/subdomain point to a branch deploy with a CNAME?

From what I’ve read, you can point any non-apex domain to a branch deploy by adding a CNAME record on that domain with the name of the branch, i.e. <branch-name>.<custom-domain> to <branch-name>--<site-name>

Would it also be possible to add another CNAME record to alias this subdomain? For example, a CNAME that points <alias>.<custom-domain> to <branch-name>.<custom-domain>?

At this time, it’s only possible to utilise the branch name for the subdomain (unless you set up another site and serve the branch separately).