for the mix, i do it like this...

my @switch_list_files = ();
my @switches = ();

GetOptions (
        'list=s' => \@switch_list_files,
        'switch=s' => \@switches,
) or die Usage();

@switch_list_files = split(/,/, join(',', @switch_list_files));
@switches = split(/,/, join(',', @switches));

foreach my $file (@switch_list_files) {
        if (open F, "<$file") {
                while (<F>) {
                        chomp;
                        push @switches, (split /\s/, $_, 2)[0];
                }
                close F;
        } else {
                die "no readum $file: $!\n";
        }
}

die "need some switches!$/" unless @switches;

__END__

$ prog -s 192.168.254.1 -s 192.168.254.2,192.168.254.3 -list foo.list 
+-f bar.list,bat.list

$ cat foo.list
192.168.250.1  rest is ignored
192.168.250.2  ditto
[download]

which takes any number of switches in any number of files or specified by any number of options.