Irule

I have to got two group of users both using same Virtual server but different set of client certificate from two different CA, I have an existing irule which checks for the valid the certificate is from the valid CA and removes the CN and passes to webserver. but now I have to add the other set of user using different in the same irule , but in case of this group the irule would check the CA and remove CN and would pass the request to APM for ldap Authentication.please would you help to create an irule for this scenario