Thank you very, very much to all repliers.

Sorry, I was not aware of the meditation from June. Though I think my inquiry gave room for deepening the insight and even showed new ideas (japhy's demonstration of using (??{})).

I think I still need some time to elaborate if, where and why I now saw the ultimate elegant solution to the problem. At least it seem clear that I don't have to wait for the "5 Unicode-character long operator from Perl6" ;-)

Thank you and good night for now.