However, I still want to get AUTOLOAD called

It will. The question is, which AUTOLOAD? More precisely, AUTOLOAD in which package?

In the example you wrote, Perl will search for AUTOLOAD in the abc::xyz package and any other packages up the @ISA chain. In other words, it won't look for AUTOLOAD in the abc package (unless abc::xyz ISA abc).

More detail on AUTOLOAD is in perlsub.

Unless I've completely misunderstood your question....