There seemed to be an inconsistency in the various example rules given for -x; whatever the case, the first step I would take is to define the usage rules clearly insead of by example, e.g.:

    [-x argx1 [argx2 [argx3]]]
    [-y argy1 [argy2]]
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or whatever it should be.

Although a module may or may not be suitable for this, my own approach when the requirement gets too deviant from norms is to:

1) define the rules in a control hash

2) hand-build the required getopts module, deriving everything from the rules you defined.

In this case, I get something a bit complicated that looks like this, but who knows, someone might know a module that does all this...(warning untested!)

my %controlCentre = ();
$controlCentre{ ALLOWED }{ x }{ MIN } = 1;
$controlCentre{ ALLOWED }{ x }{ MAX } = 3;
... etc.

GetOpts( ctrl => \%controlCentre );

#
# at this point actual options and arguments have been
# loaded into the control hash in the form
# $controlCentre{ ACTUAL }{ option-letter } = argument-array
#

sub GetOpts {
    my %par=(@_);
    while ( $ARGV[0] =~ /^\-(.)$/ ) {
        my $opt = $1;
        $par{ ctrl } -> { ALLOWED }{ $opt }
            or Usage( ctrl => $par{ ctrl });
        shift @ARGV;
        my $minAllowed
            = $par{ ctrl } -> { ALLOWED }{ $opt }{ MIN };
        my $maxAllowed
            = $par{ ctrl } -> { ALLOWED }{ $opt }{ MAX };
        $par{ ctrl } -> { ACTUAL }{ $opt } = [];
        $aref = $par{ ctrl } -> { ACTUAL }{ $opt };
        for ( my $i = 1;
              $i <= $maxAllowed;
              $i++ ) {
            if ( $ARGV[0] =~ /^\-(.)$/ ) {
                ( $i >= $minAllowed )
                    or Usage( ctrl => $par{ ctrl });
                last;
            }
            else {
                push @$aref, shift( @ARGV );
            }
        }
    }
    # leftovers must have disobeyed the rules...
    $ARGV[0] and Usage( ctrl => $par{ ctrl } ); 
}

sub Usage {
    # even the Usage message is driven by the defined rules
    my %par = (@_);
    print STDERR "Usage: $0 ";
    my $allowRef = $par{ ctrl } -> { ALLOWED };
    foreach ( sort keys %$allowref ) {
        print STDERR "-$_ ";
        my $minAllowed
            = $par{ ctrl } -> { ALLOWED }{ $_ }{ MIN };
        my $maxAllowed
            = $par{ ctrl } -> { ALLOWED }{ $_ }{ MAX };
        for ( my $i = 1; $i <= $minAllowed; $i++ ) {
            print STDERR "arg${_}${i} ";
        }
        $maxAllowed and print STDERR "[ ";
        for ( my $i = $minAllowed + 1;
              $i <= $maxAllowed;
              $i++ ) {
            print STDERR "arg${_}${i} ";
        }
        $maxAllowed and print STDERR "] ";
    }
    print STDERR "\n";
    exit 1;
}
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-S