Chats can only be started by Group Owners or Admins. The Group Owner or Admin must be present for the entire chat in order for the chat room to stay open.
Here's how to join a chat in your group:
Mouseover 'Groups' tab.
Click on 'My Groups' in the drop-down menu.
Go to your group's homepage.
Click the 'Chat' link on the left side of the page.
In the yellow box, click on 'Click here to join'.
A pop-up window will appear on your screen and the chat room will open.
look for groups you want then join the group, theres usually a join group, or apply to group button somewhere on the page, just scroll down to look for it. After you do that you wait for a e-mail that welcomes you to the group. Then you can join the chat.