CRM 2011: Modify the fetch xml of an associated view (Left Navigation) dynamically

Hi, 

we have a requirement to show all related records fr the current record and it's child entity records in one single view. 

For example, I want to show all the Activities related to an Account, it's child contacts, it's child cases etc in one view. If we add a subgrid I know we can dynamically set the fetchxml for the grid to change the results. 

subgridElement.control.setParameter("fetchxml", dynamicFetchxmlstring);

Can we achieve the same functionality for a left navigation item? - i.e. When I click on the 'Activities' left navigation on an Account form I want to see all related Activites (parent, children). So is there a way to set the fetchxml dynamically when the left navigation link pane loads ? Is it supported?

Please help. 

Thanks