Zimbra Instant message with buddy list

[cappuccino]

Hello everyone,
I'm using Zimbra CS 5.0.18 with centos. My company has policy that prevent users from using external IM services like google, yahoo, msn or AOL... So I plan to use Zimbra IM for all company accounts.
Problem is employees dont want to add contact to his/her buddy lists manually, I already search around google, zimbra wiki and this problem to find a solution to customize Zimbra IM service (If possible), but there's no topic about this subject.

So someone please tell me how can I add contact automatically from global contact list to IM service without adding by hand one by one.

Thank you very much.

--h

[primaxx]

I am also curious about whether this is possible.
(Zimbra CS 6.0.1)