Check fields Responsabilities WBS and WBE

Hi,

I d like to control a WBS and WBE with the responsible persons( PROJ-VERNR) and (PRPS_VERNR). Exactly a responsible persons "A" can only  change (CJ02-CJ20n), change original budget (CJ30), display original budget of him WBE (CJ31) and not change the value the wbe of the others responsible persons.

For example:

1- WBS responsible persons is A

2- WBE responsible persons is B

2- WBE responsible persons is C

3- WBE responsible persons.is B

3- WBE responsible persons is A

I tryed with validation of wbe without success.

I ask if there 's some exit or badi about this.

Can you help me?

thanks

Best Regards.

Sandro