InfoPath Dev

Hello, I've created 4 lists in SharePoint 2010. - Country (Country) - City (Country, City) - Location (Country, City, Location) - Information (Title, Location, City, Country) Then, I've developed InfoPath forms for all the lists. In the Location InfoPath form, I've done this using InfoPath functionality of cascading drop down so that when i select Country, it filters the Cities related to selected Country. Now, the issue arrives in the Information List InfoPath form. Here, I've to select in the reverse order. Means, user will select Location which will filter the City & Country. How can we do this ? Any idea ? Thanks