After a little guess and check, I added the following line to the Common.config file:

 

<define name="InsertLink" text="[[InsertLink]]" command="InsertLink" image="link" />

 

Then to get it to show up in a menu, I added this to the <SubMenu> section in <define name="EditGroup"...:

 

<ref name="InsertLink"/>

 

Now, the Insert Hyperlink menu option appears and works in the Edit Group sub menu.

 

My question now is how to get this menu item to appear on the main context menu, and not in a sub menu.  Thanks for your help!