my (%passed, %failed, %untested);
%passed = { 
    MSIE50NT => 1, 
    MSIE55NT => 1, 
    URI_REDIRECT => 'http://passaddress/', 
};
# set %failed and %untested

my $br_detect = 'palm'; # as found by HTTP::BrowserDetect
if( defined $passed{$br_detect} ) { redirect( $passed{URI_REDIRECT} ) }
if( defined $failed{$br_detect} ) { redirect( $failed{URI_REDIRECT} ) }
defined $untested{$br_detect} ? '' : %untested{$br_detect} = 1;
redirect( $untested{URI_REDIRECT} );

sub redirect {
# your redirect logic here...
}