2 Dimensional arrays?

Is it possible to get back 2D arrays from a form?

 

I want to be able to have a table with some number of rows. Each row has a
'grouping' field which the user can enter a number in. Each row will also
have a dynamic 'foo' column which will have a button to add additional 'foo'
values. Some javascript will drop in new 'foo' textfields on a given row
whenever that row's button is clicked.

 

I want to be able to collect an int[] grouping array, which is straight
forward. Iterating over a collection to create textfields will let me get an
int[] in my action which will be the list of groupings indexed by row (so
grouping[0] yields the entered value for the first row, grouping[3] yields
the entered value for the fourth row, etc.)

 

I also want to be able to collect an int[][] foo array. This should be an
int[] array of foo values indexed by row. This is less straightforward and
I'm not sure how to approach this. Are there any sorts of similar examples
to this floating around?