Creating dynamic nested GridView

I've run into an interesting problem. I have multiple sections in a report that I create dynamically at runtime. These sections are in the form of GridViews. I have to create them dynamically because, at any given time, there's a variable number of these sections.
Within each section, there will be numerous comments. I'd like to use a GridView for this as well and nest the comments GridView inside one of the columns of the parent section GridView.
Here's the problem. I know I have to create a new ITemplate class that uses InstantiateIn in conjunction with the TemplateField I am dynamically creating in my section GridView. But for the comments GridView, if I'm going to bind it to a database, I need to access the Section_ID field that resides in another column in my parent section GridView. Can anyone tell me how I would go about doing that? 
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