After a user expands a group by clicking the + symbol, can I read the embedded rows within the selected group. 

Simple example. Fifty US state groups with each state group containing cities [rows] with populations over 100K. I need to be able to read the rows of a selected state.

Can I incorporate a checkbox at the group level to set checkboxes within a selected Group to true?

Another question. Clickiing on the rowselector i can select multiple rows within a group by using the ctrl/shift key. How can these selected records be read?

Any insight would be helpful.

Thank you.