Manager Hierarchy for compensation plans

Summary:

Hi There are few requirements from the clients on how to build the manager hierarchy for their compensation plans. Appreciate any thoughts and solutions

Content (please ensure you mask any confidential information):

1. Any compensation (Salary Inc, Bonus, LTIA, Deferred Shares) will require approvals from the senior manager, following up each level in the hierarchy from eligible G4+ level Managers up to CEO's direct reports (business leaders). That means they will use the Line Manager hierarchy as the source for Primary Hierarchy but LMs below G4 who has less than 5 direct reports won't be doing any review and their direct reports will be rolled up the their managers. I believe it is something that can be achieved by fast formula?