Service to Return a Structure

I've created a gateway service based on a function module.

It returns values in the READ operation based on the primary key.

It returns several structures and some of those structures have several entries- for instance appointments.

It will only return one appointment no matter how many entries there are.

I was hoping for all the appointment records to be in a nested XML structure that I can bind to table rows.

I know this is possible, I'm just not sure of the method. Can someone describe the process to me?

Thanks.