Hello, I am working on implementing Oracle HR,(HR only installation w/o payroll) I dont think this is possible but my client is insistent. Does anyone know if it is possible to implement PTO Accrual plans for multiple countries/legislation in the same business group? If yes, can you please provide any details. I very much appreciate your help!

You can't have multiple Oracle legislations in the same Business Group. You can have multiple countries (provided they use the same legislation, of course) by setting them in the hierarchy.