GAL is the list of the users configured in Smasrtermail... You cannot edit it without change the users.
Only changes in SmarterMail users has effect to the GAL.
It's the same as MS Exchange...
Gabriele Maoret - Head of SysAdmins at SERSIS
Currently manages 6 SmarterMail installations (1 in the cloud for SERSIS which provides services to a few hundred third-party email domains + 5 on-premise for customers who prefer to have their mail server in-house)