As an example of what 1nickt suggested, maybe something like:

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -e
"my @files = qw(
   TUMI-1354839054_alt1 1.psd
   maur-1111.psd
   Sam-I-Am.gif
   maur-1110.psd
   );
 ;;
 my %user_tag_title = qw(TUMI TUMI  BW BW  maur maurices);
 ;;
 my ($rx_user_search) =
   map qr{ $_ }xms,
   join ' | ',
   map quotemeta,
   reverse sort
   keys %user_tag_title
   ;
 print $rx_user_search, qq{\n};
 ;;
 my %files_seen;
 FILE:
 for my $file (@files) {
   next FILE unless my ($user) = $file =~ m{ ($rx_user_search) }xms;
   push @{ $files_seen{$user} }, $file;
   }
 dd \%files_seen
 ;;
 USER:
 for my $user (sort keys %user_tag_title) {
   next USER unless exists $files_seen{$user};
   ;;
   printf qq{%d $user_tag_title{$user} files \n%s \n\n},
     scalar(@{ $files_seen{$user} }),
     join qq{\n}, @{ $files_seen{$user} };
   }
"
(?msx-i: maur | TUMI | BW )
{
  TUMI => ["TUMI-1354839054_alt1"],
  maur => ["maur-1111.psd", "maur-1110.psd"],
}
1 TUMI files
TUMI-1354839054_alt1

2 maurices files
maur-1111.psd
maur-1110.psd
[download]

For a discussion of how  $rx_user_search is built, see haukex's Building Regex Alternations Dynamically.