Many times a lively discussion forms on the main forum because members become confused and do not realize that they are not actually in the group but only reading an announcement about a group activity.
If you would like to advertise your group or something going on in your group, "you can have your cake and eat it too", as the saying goes.In other words you can make an announcement only and direct people to your group.
What you can do is create a promotional announcement on the main page in the main forum but click on
the button which says "discussion closed". This will prevent conversations from taking place in the wrong place. Then you can divert the "action" back to your group where you want the conversation to take place.
Many group moderators are experienced with social networks, and take for granted that members know how to navigate around a site. But experienve has shown that we have to help members learn this new way of communicating.
So I encourage al of you to help members get comfortable on the site. Feel free to clariofy and help membrs learn how to use the site.