Task Manager attribute in Invoice Approval BPM Worklist

We have a client's requirement to fulfill were it as below:

There are 3 Project Managers assigned to a Project where they will be Task Managers also for some tasks.

E.g. Task No. Project Manager

1 ABC

2 DEF

3 XYZ

The Invoice approval needs to flow to the respective Task manager assigned to that task. Currently, invoice approval flows to all task managers/ project managers assigned which caused irrelevant information for non-assigned Task Manager/Project Manager. I have searched for this on the BPM worklist but could not find Task related conditions in the approval payload. Please guide how to achieve the above requirement of the Task Manager