I have a lottery template that basically does what you're describing. I created a set of Global Lists for each state in our group. I then created a text box with a static list and entered the names of my Global Lists as the selectable values:

I created a second text box with a Global List data source and entered the name of the first text box as the source using the @TextObject@ macro. My first text box was named "State Lotto" so the value that I entered was @State Lotto@

Now when the state is selected in Sequence, the list of games available changes in the second dropdown.


So in a nutshell the first textbox contains the names of global lists (in your case NBA, NFL, etc.), and the second text box fills in its values based on the global list selected in the first. Hope this helps!
#XPression