Muckety
I stumbled upon this website, but it is fairly cool. You can enter a name from the political establishment and see all of the connections. For example, one of my US Senators is Mark Warner (D-VA) and above you can see his Muckety map. This might be a fun assignment for your students to look at in class and it could be an assignment to look up some of the groups. Click on any of the + signs to see a new web.