Avoiding Circular Dependency

Question

I have a four projects in a solution AllianceControl

-MainMenu

-BackflowControl

-UMS

-CounterReceipts

MainMenu Serves as launchboard for all the different projects as refrences them all to get at the controls to launch in a tab control:

BackflowControl -> MainMenu

UMS -> MainMenu

CounterReceipts -> MainMenu

EX:

http://s1024.photobucket.com/albums/y307/USSDeveloper/?action=view&current=datagridpull.png

This setup worked perfectly while I had just needed the refrence one way. But I came across a problem when I needed to add a new feature. Say I'm in BackflowControl 

and want to load account information off of a datagrid double click. This double click would open a new tab in the collection I have going on. My problem is that the 

functionality and collection is stored in my main menu since that is the launching point. I understand of course that you can't refrence the Mainmenu from the controls

(this would cause circular dependancy) but how would I be able to get at the function (or collection of tabs) to create a new tab in that collection?