Quirky question about rewriting usernames

[Cliff Cole]

Hello all.

Here is my issue.  This is very weird and would only affect one NAS.
I'm not sure freeradius is capable of this.  I want a username that
comes in to check for an @domainname.  If the domainname is there I
want it to be stripped and added back later.  If the domainname is not
there I'd like it to continue and have to domainname added later in
the authentication process.  I hope this makes sense and any help is
appreciated

Cliff