RPC pagination? Partial pagination?

Is it possible to do pagination in an RPC?
Is it possible to do pagination on only a portion of the data?

I have defined an RPC web service that calls an external (soap) web service. That web service returns to my web service both “header” info and an array of “detail” information. (I do some massaging of the data, but the result is the same (header and an array of details)) The details array can get really large. So I would like implement pagination. But pagination is not typically used in an RPC in Api Tools (Apigility). To make it more difficult, I really only want to implement pagination for the details portion if that is possible.

This is a mock-up of what the results of my web-service look like now (try to imagine many, many elements in details)

"results": {
	"header": {
		"order_number": 987654,
		"customer": "Olive P. Aychpee",
		"last_updated": "2020-11-1812:45MST"
	"details": [
			"transaction_id": 123,
			"product_id": "WIDGET-27",
			"amount": 47.47
			"transaction_id": 124,
			"product_id": "GADGET-84",
			"amount": 12.32

Any advice would be greatly appreciated!

Since you are already massaging the external data, I assume you have it in an array.
From here you should be able to separate header and details. Now it shouldn’t be to problematic taking in page and limit parameters from our own RPC call and return only the parts of the array you are requesting with the header attached to it. The RPC itself should be REST, but that’s besides the point.