Hi Salman,
One important point is the implementation of OM is not based on SAP best practice and this cause the issue.
As you know SAP best practice is having one position for each EE not to assign many EE to a single position. If they have done such a thing to use in workflow I should mention the standard way is having TASKs in OM and assign them to Jobs, Positions, Organizational Units and so on and then develop workflows based on TASKs each Position, for example, is responsible for.
Now let's back to your issue. Why you would have restricted access to PPOME? You need this for HR Administrative Stuff or for each department's manager? What they will do in PPOME?
If they need to create OM objects thru PPOME I think there is solution. Please clarify your issue.
Regards,
Omid