my %switch = (
  "host1.com" => \&DoAction1,
  "host2.de"   => \&DoAction1,
  "host3.xyz"  => \&DoAction2,
  "host4.das"  => \&DoAction3);

if (exists $switch{$element} and ref($switch{$element} eq 'CODE') {
  $switch->$element->($param1, $param2, $param3, ...)
}
else {
  die "Error: no action for '$element' specified\n";
}
sub DoAction1 {
  my ($p1, $p2, $p3) = @_;
  print "Action1\n";
}
sub DoAction2 {
  my ($p1, $p2, $p3) = @_;
  print "Action2\n";
}
sub DoAction3 {
  my ($p1, $p2, $p3) = @_;
  print "Action3\n";
}