Core Data and Cocoa Binds

First of all, I'm fairly new to programming with Cocoa.  With that said, I am writing a scoreKeeping application for softball.  Eventually I want to put it on the iPhone, but I'm starting out just on the Mac.

Basically I want the program to keep stats for multiple players on multiple teams.  Core data makes this pretty easy.  I have an entity for Team and an entity for Players.  There is a to-many relationship between the two (which is inverse also).  I have two PopUpButtons.  One shows the teams.  The other shows the players that are on the team selected on the other button.  Cocoa bindings make the first one very easy.  I set up an Array controller that is hooked up to the ManagedObjectContext and holds Team entities.  Great.  Then I bind the pop up button to the teamName of that ArrayController.  Very simple.  If I do the same thing for the Players, it will display all of the players in the whole app.  Not just the players on the team selected.  I know there is a FilterPredicate on the ArrayController that will solve this for me.  I just don't know how to set it up.  I understand how to make predicates (I use them when I fetch stuff from core data), but I don't know how to bind it.  Also it needs to update everytime I switch the team selected, so that would require some observer hand shaking.

I think this very simple example really shows the power of cocoa.  Laying something out like this would be very helpful to a lot of people I'm sure.

Please help if you can!

Thanks in advance!