I have a Wingrid which has several bands. Customer, orders, items.

I would like the Customer band to load the entire table as it will not grow too large (i.e. thousands ) and it only when the program starts.  However, I would like the child band (orders)  to load it's rows from the database only when the user clicks on the + sign, by querying the database with a where clause based on the relationship.  How can I defer the data load  for the child bands?