Board Thread:The Quarters - Q & A/@comment-24515084-20140207000038/@comment-24185151-20140209034529

This can be achieved by clicking on "edit" in the side bar of your guild page. This will give you the usual editing of your guild description, but will also open up a new section on the right hand side where you can make announcements. :) It says in grey: "message from group leader"

I hope this helps you.