Hi Salman,
you may need an ABAPer, but probably only for a few lines.
You definitely need soemone, who really understands structural authorisations.
Of course, if you start assigning structural profiles, it will affect the HR org structure and it will also affect all other PD objects (as in training&events management/LSO, qualification catalogue, performance manageemnt,...).
You must be aware that structural authorisation can be switched on and off for PA-data, but is always active for OM and other PD objects. YOu may just not be aware of it, because all users are per default assigned to an "ALL" profile (the profile assigned to SAP* in T77UA), as long as you haven't assigned anything else to the other users in T77UA - meaning nobody has got any restrictions through the structure (there may still be restrictions through object PLOG). As soon as you assign anything to a user, you need to assign his full scope of PD objects.
A lot ha sbeen written on structural authorisations on SCN, so I'm not doubling up. Just take the above warning about moving away from the default as a starting point to make yourself familiar with the full concept.
Once you really know what outcome you need, you can involve an ABAPer to build the right function modules to go into T77PR for you, if at all necessary. Though, the programming exercise is probably really simple, so the normal ABAP knowledge of any non-junior HR consultant should be enough.
kind regards
Sven