Defining a relationship with a repeating field

Apologize in advance for the probably simple question, but the solution's been eluding me...

I have two databases: one contains about 6000 records of sales leads, the other contains about 12 dealers. A dealer is assigned a territory by states; territory is currently defined in the database as a repeating field (up to 10 values; though no dealer covers 10 states, some do cover more states than others). I am trying to create a relationship that displays through a portal ALL sales leads in the dealer's territory, but I can only get it to display one state in the territory at a time as it won't recognize ALL the values in the repeating field. Also, I'd like to create a total so I can see how many sales leads that dealer's territory contains.

Any hints or advice would be appreciated. Maybe I've made this more difficult than it needs to be! I understands this forum isn't school, so I'm more than prepared to learn on my own...but a few ideas would really help. Also, any recommended reference books that I could acquire that goes beyond the product's <useless> user guide would also be appreciated.

Thanks!