Redirect a non-existent subdomain to a regular URL

I have amalgamated all sites on a server to a multisite setup and all domains are now "parked" on the server: - all is well

An old domain which was set as a subdomain on shared server is now simply "parked" and redirected using the domain mapping plugin.

This subdomain is removed:

the contents are now moved to:

The multisite network domain is:

In short I need to redirect: to

Should this be done at the domain registrar level or can it be handled locally at the server?

Thanks in advance