Deep Subgrid Query: Show other contacts that share the same Parent Customer (Account)

I thought I'd throw this out and see if anybody can offer any help, or let me know if what I want is simply not supported within the existing "Deep Subgrid Query" functionality (http://blogs.msdn.com/b/crm/archive/2012/04/16/deep-queries-for-subgrids.aspx).

I have built a handful of these, but have never done one like I detail below:

On the Contact record, I would like to display a grid showing all contacts that share the same Parent Customer (Account). For this we can assume that only Accounts will be used as Parent Customers.

Example: Tom, Dick, and Harry work for XYZ company. Opening Tom's record would show a grid with Tom, Dick, and Harry in it.

Is this possible?

Thanks in advance,

-James