Similar solution, but not with single regex: 
#!/usr/bin/perl

use strict;
use warnings;

# https://perlmonks.org/?node_id=11148806

my $text = 'This is arbitrary just an arbitrary just example of text j
+ust arbitrary.';

@_ = qw( ju.. arb.{1,4}ary );

$text =~ m/
    (?:(?:This)|(?:That))
    .*? (??{ $_[ 0 ] })
    .*? (??{ $_[ 1 ] })
    /x and
    $text =~ s/
    (??{ "(*FAIL)" x ! @_ })
    .*? \K ( (??{ $_[ 0 ] }) ) (?{ shift @_ })
    /<<<$1>>>/gx;

print $text, "\n";

[download]
OUTPUT (excluding warnings): 
This is arbitrary <<<just>>> an <<<arbitrary>>> just example of text j
+ust arbitrary.

[download]
P.S. capture group is redundant.

In reply to Re: Highlighting only captured groups from larger regex by rsFalse
in thread Highlighting only captured groups from larger regex by Polyglot

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.