separating Useres

Hi Guys,  i have freeradius 3.0.15 and Mysql DB  we use MAC authentication so everyone allowed to connect if they are not exceeded their limits. (anonymusers ,  not exist in DB ) In   /etc/freeradius/3.0/sites-available/default   I have  update control {                 Max-Daily-Session= 1800          }          update control {         Acct-Output-Octets := 307200          }  So by default every user has 1800 Seconds and 300 Mb daily limit is there anyway to  make exception for some users ?  like 7200 seconds and 1 Gb daily limit Thanks