[Kamailio-Users] Textops / Search / Regex

Hello, I currently have the following search method use: search("(restricted|anonymous|Anonymous|Private|private|Unknown|unknown)") unfortunately this is catching cases where there is a Diversion header i.e. Diversion: < sip:1234@someHost > ; reason = unknown So I attempted to do an assertion: search("(restricted|anonymous|Anonymous|Private|private|Unknown|(?<!reason=)unknown)") However it does not seem that Kamailio is completely PCRE compatible? thus server fail.... / parse error Does anyone have a solution so I can keep the same matching, except exclude matching "unknown|Unknown" when reason=unknown, however match it in all other conditions? Thank you for any and all help ahead of time. Sincerely, Brandon