Expand all existing data in servicefunction result

I have service getdailypurhacedeliveries(date: tdatetime):tlist;
tpurchaseorder has rows and and each row has deliveries. PurchaseOrders and Rows have other subentites which aren't needed here.
Can I tell xdata to expand all subentities which have been loaded?
Cause this is specific service to get specific data i don't like idea that caller should use expand header

After reading manual again, I think answer is no. I'll just have to document to use $expand...

Maybe you can use xdata-expand-level HTTP header: TMS Aurelius CRUD Endpoints | TMS XData documentation.