my @strs = qw/
    ABCBXBCA
    APCBXBCAC
/;
my @patterns = (qr/B.B/, qr/CB/); # See comment below.

my $matched_pattern;
my $all_pats = do {
    use re 'eval';
    qr/(.*?)(?:@{[join '|', map "$patterns[$_](?{\$matched_pattern = $_})", 0 .. $#patterns]})/;
};

foreach (@strs) {
    print "String:$_ Pattern:$patterns[$matched_pattern] KeyWord:$1\n"
        if /$all_pats/;
}