Response tag with URL parameter - rest

Question

Is there any way in an Insomnia request to use the response body of a sub-request in the request body, and at the same time specify a URL parameter for that sub-request?
Consider an API with endpoints like these:
[GET] _.base_url/customers/{id}
[GET] _.base_url/products/{id}
[POST] _.base_url/invoices
When POSTing to the invoices endpoint, the API expects a JSON body along these lines (highly simplified, of course):
{
"date": "2022-03-31",
"currency": "USD",
"customer": {
"id": 123,
"name": "Something Corp.",
"address": "Here, there and everywhere"
},
"items": [
{
"id": 456,
"description": "Thingamajig",
"price": 11500
},
{
"id": 789,
"description": "Doodad",
"price": 23900
}
]
}
That is, it expects the customer field and each of the items fields to be full objects, not just IDs. (And yes, that’s stupid and not RESTful, but I don’t control the API.)
The proper way to retrieve such objects would obviously be to call the two GET endpoints with the IDs as part of the URL, and then using the responses as response tags in the POST request – but I cannot find a way to do this.
There’s a lengthy GitHub discussion on per-request veriables which has so far not produced any results, but even the suggested PR in that thread doesn’t seem like it would support defining the URL parameters when calling the request, rather than in the request itself.
Is there some way to achieve this in Insomnia?