use strict;
use warnings;

my @group1 = ('A','B','C','D');
my @group2 = ('E','F','G','H');
my $string="DEABCDGHEF";
local $" = '';
print "Match: $1\n" while $string =~ 
    /([@{[@group1[0..2],@group2[2,3]]}]{5})/g;