my @multi_sorts = (
    [ $array1, ':', 'num' ],
    [ $array2, '-', 'alpha' ],
    [ $array3, ',', 'num' ],
);

handle_multi_mixed_sorts(\@multi_sorts);

# At this point in the code, each of the arrays in @multi_sorts
# has the original array still as the first element
# and the sorted array now as the fourth element.

sub handle_multi_mixed_sorts {
    my ($multi_sorts) = @_;

    for my $i (0 .. $#$multi_sorts) {
        push @{$multi_sorts->[$i]}, [
            sort { split_sort($a, $b, 
                    $multi_sorts->[$i][1], $multi_sorts->[$i][2])
            } @{$multi_sorts->[$i][0]}
        ];
    }

    return;
}