[Freeswitch-users] mod lcr cid conditional replace.

Hi. I use mod_lcr for dialout operators. On the freeswitch pbx we have extensions 500 to 899. When calling outside number the internal extension is converted ok to for external cid to be accepted by each operator using lcr_cid regular pattern: /(\d\d\d)/${operator_prefix}$1/ The problem lies with one operator where our extensions which start with 5 (500 to 599) must be converted to numbers which start with 9 (900 to 999) and then prefixed with operator's prefix. The rest of extensions does not have such a substitution of first number. How can I do this using regular expression in lcr_cid? Thank you.