REST API / Get current business data of multi-instantiated task

Hello.

I'm trying to make a multi-instantiated task, based on the case business data which is marked as multiple, ie a list.

The process design seems to work when I test it from the studio : instances of the task are created according to the number of elements in my business object list. The current object, with the right type, is given by the iterator task variable, and the operations at the end of the task update the business object with the contract attributes as expected.

Now I'd like to retrieve from the REST API the current object that is given by the interator. The goal is to identify for each instance of the task the associated business object, and then update it with input values.

What is the right wy to do that ?

Thanks for your help.

Regards.