If you use a named capture, then you can use that capture for a subsequent match, perhaps a new regex. ... using a named capture this way in a new regex ...

Could you give an example of what you mean? AFAIU, the  %+ hash is re-initialized when a new regex match is entered.

c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = 'one two three four';
 ;;
 $s =~ m{
   \A
   (?<save>  \w+) \s+
   (?<this>  \w+) \s+
   (?<for>   \w+) \s+
   (?<later> \w+) \s*
   \z
   }xms;
 print join '-', @+{ qw(save this for later) };
 ;;
 $s = 'fee fie foe fum';
 ;;
 $s =~ m{
   (?{ print join '==', @+{ qw(save this for later) } })
   \A
   (?<save>  \w+) \s+
   (?<this>  \w+) \s+
   (?<for>   \w+) \s+
   (?<later> \w+) \s*
   \z
   }xms;
 print join '+++', @+{ qw(save this for later) };
"
one-two-three-four
Use of uninitialized value in join or string at (re_eval 1) line 1.
Use of uninitialized value in join or string at (re_eval 1) line 1.
Use of uninitialized value in join or string at (re_eval 1) line 1.
Use of uninitialized value in join or string at (re_eval 1) line 1.
======
fee+++fie+++foe+++fum
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To do something like you suggest, you would have to "capture the capture" in a separate set of variables before the new match was entered.