"switch" statement": would you know a more compact statement?

[Alex Zetaeffesse]

Hi FR people,

Is there a more compact way to state what follows?

        switch {
                ("%{User-Name}" =~ /@tenant101\.bic\.local/) {update
control{Proxy-To-Realm := "tenant101"}
                ("%{User-Name}" =~ /@tenant102\.bic\.local/) {update
control{Proxy-To-Realm := "tenant102"}
                ("%{User-Name}" =~ /@tenant103\.bic\.local/) {update
control{Proxy-To-Realm := "tenant103"}
                ("%{User-Name}" =~ /@tenant104\.bic\.local/) {update
control{Proxy-To-Realm := "tenant104"}
                ("%{User-Name}" =~ /@tenant105\.bic\.local/) {update
control{Proxy-To-Realm := "tenant105"}
                ("%{User-Name}" =~ /@tenant106\.bic\.local/) {update
control{Proxy-To-Realm := "tenant106"}
                ("%{User-Name}" =~ /@tenant107\.bic\.local/) {update
control{Proxy-To-Realm := "tenant107"}
                ....
                ("%{User-Name}" =~ /@tenant170\.bic\.local/) {update
control{Proxy-To-Realm := "tenant170"}
        }

Eventually, I may get the value of the Proxy-To-Realm variable, by
stripping the 2nd and top level domain and there would not need to repeat
the case.
Thanks,

Alex