[squid-users] One group with LDAP, another not

Hi all!
Looking in the docs I can´t find this.
Is it possible with acls or something?
one vlan, for example 172.17.15.0 must authenticate with LDAP server for
use squid.
another vlan, for example 172.17.31.0 can use squid without authentication.
Suggestions? Info about this?
Thanks a lot.

-- 
Carlos Martínez-Troncoso Cera
Coordinador de Servicios Internet/Intranet
Universidad del Norte
Barranquilla, Colombia