You can do something like this to get your desired results Effectively we only do the substitution if we have a match in $2 as well as $1 which means we have to have "SOMETHING rice" where SOMETHING is the maximum non exclusive OR of the presented cases.....

my $jdsc   = qr/(?:national\s+security\s+adviser\s+)/;
my $title  = qr/(?:dr.|doctor)\s+/;
my $fn     = qr/(?:condoleeza\s+)/;
my $sn     = qr/rice/;
my $repl   = 'condoleezarice';

while(<DATA>){
    s{ ( ( $jdsc? $title? $fn? ) $sn ) }
     { $2 ? $repl : $1 }exig;
    print;
}
__DATA__
white rice
dr. rice 
doctor rice 
dr. condoleeza rice 
doctor condoleeza rice
condoleeza rice
national security adviser doctor condoleeza rice
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Update, I prefer Sidhekins method

s/ (?!$sn) $jdsc? $title? $fn? $sn /$repl/igx;
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