Filter some web folders and mod_cas

[Umut Arus]

Hello,

There is a folder in the location of authenticated by CAS that we want 
to restrict some users (on the LDAP tree as Alumni, Retired etc...). Is 
there another way to do this differ from mod_cas as filtering cas on the 
fly?
Or may be another solution, I have installed mod_cas but I haven't 
understand why it is directory listing disable by mod_cas? If directory 
listing could be enable how to this works?

Thanks.