...
use CGI;
....

# Query all variables
my $button = $query->param( "button" );
my $username = $query->param( "user" );
my $region = $query->param( "region" );
my $var1 = $query->param( "var1" );
my $var2 = $query->param( "var2" );
my $var3 = $query->param( "var3" );

if ( $button eq 'first' ){
	display_first( $username, $region, $var1, $var2, $var3 );
}

if ( $button eq 'second' ){
	display_second( $username, $region, $var1, $var2, $var3 );
}
...
...


sub display_first{

	my ( $s1_username, $s1_region, $s1_var1, $s1_var2, $s1_var3 ) = @_;

	.....
	.....
	do something with the variables...
	.....

}

sub display_second{

	my ( $s2_username, $s2_region, $s2_var1, $s2_var2, $s2_var3 ) = @_;

	.....
	.....
	do something with the variables...
	.....


}