samba - Aug 2010 - HOWTO give rights access using computer name ?

Dear

I have a 3.5.4 Samba sever and some specifics shared folders used for 
robots (backup, mails etc...)

Passwords, users should be changed regulary and this require to change 
the code in shell scripts for mounting remote shares.

I would like to specify access rights by computers name in some shares 
section in the smb.conf .

Is it possible to do that ?

currently i user a public share but it is not really a good solution

bets regards