Get shorthand session values in irule from ldap query

I have a policy that issues a LDAP query after a user is authenticated. The query retrieves back all the "memberOf" attribute from AD. When I look at the session variables in F5, I can see all of my data, which looks something like this:

`be92fd82.session.ad./Common/cool-access-policy_act_active_directory_query_ag.attr.memberOf`

| CN=Cool_Administrators,OU=COOL Users,OU=Users,OU=UCOP,DC=COOLS,DC=Net | CN=Domain Users,CN=Users,DC=COOLS,DC=Net | CN=MAINS Users,OU=App-Groups,OU=MAINS,OU=Bus,OU=Ent,DC=COOLS,DC=Net | CN=Users,CN=Builtin,DC=COOLS,DC=Net |

I want to loop through these values in a IRule, after the query is successful, and insert them into the header, but only the CN values.

I know I can insert the headers like this:

`when HTTP_REQUEST  {
          HTTP::header replace username "coolio"
          HTTP::header replace roles "Cool_Administrators,Domain Users,MAINS Users"
          HTTP::header replace domain "COOLS"
    }`

But I do not know how to loop through and split the array into CN values.