How to make Syncronus/parellel calls on Apigee using other then Node js approach as it is not feasible presently on our Apigee infra

Hi all,

I have a requirement with 2 backends and 1 apigee url,

one apigee url to make parallel calls to 2 backend urls.

if response array from backend 1 has fields less than 50 then take rest from second backend response and display consolidated of 50 fields.

Responses over view

backend 1 response can be <=50 fields of json array

backend 2 response can be <=50 fields of json array

final response to client should be json array of 50 fields

How to implement this ? ( request not to recommend Node.js )

Please suggest