Unix : home directory

[chris job.fr]

  Hello,

  Our users have two home directories : a local one (/home/user1) and
the "pam directory" (/pam/users1).  When a user goes on a unix
platform of the laboratory, he is automatically on the pam directory
(/pam/users1).
  Is it possible to do this thing : if the pam directory is
inaccessible, the user is automatically on their local directory
(/home/user1).

Thank you for your suggestion
Chris
--
chrisjob.fr at gmail.com