How to set a notification summary for multi companies / Organizations

Hi all,
We are currently implementing multi-organization / multi company implementition.
We have a question regarding approvals. Is it possible for a document requiring approval to come to a single notification summary.
Currently, for the requester level, each company requires different responsibility.

So as it stands, currently we have three different responsibility to approve requests from three different companies/organization.
    Responsibilities:
    1) Request Approver A - approves PRs from company A
    2) Request Approver B - approves PRs from company B
    3) Request Approver C - approves PRs from company C

1. Can one approver responsibility have notification summaries from 3 different companies?
    ex: Request Approver 1 - approves PRs from company A,B, C