Storing Arrays within a collection?

I have a situation in which I am storing Grid Data in an Array. The functionality of my app is such that the Grid can store multiple "groups" of data, which I store in an array. My problem is that there can be multiple arrays. I have used collections in the past but I'm not real savvy with them. I'm thinking this is the best way to store my arrays. I need to be able to store each array with some kind of unique identifier but not sure how to do this. I have a field which is unique called a "Run#". I'm thinking that I can use this as the unique identifier but just not sure how to associate it to an array and then add both to the collection. Any ideas?

Thanks,