I think you are looking for code roughly like this:

my %IDs;

# when reading the ID file, for each line do something like
$IDs{$current_id} = [];

# and then for each line in the four other files:
while (my $line = <$file>) {
    my ($id, $value) = split / /, $line;
    push @{$IDs{$id}}, $value
}

# and at the very end, print them all out:
for my $id (sort keys %IDs) {
    print "$id: ", join(', ', @{$IDs{$id}}), "\n";
}
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See also: perlintro, perlreftut.

If you want to keep track about which file contains which ID, you should use something like $IDs{$id}[$file_number] = $value instead of using push.