controlling of organizational units in approp request with position id data

Dear Experts,

I am using Investment Management for PS.

I have created Investment management program and position ids, in Position ID master data, I ahve mentioned the Co area, Company Code, Plant and Business Area.

Then creating an Appropriation request using IMA11 code, in control data tab, I mention the Investment program with position ID and Organizational data tab, I am mentioning the requesting cost center and Plant, system automatically populates the other fields in that tab.

Here I want to have a check of the plant and business area of the appropriation request with that of the Investment Program position ID.

Say the plant in position id is 1000, and plant in appropriation request is 1100, system allows to save the appropriation request.

I want to stop it. Also, can system check the budget of the position id while saving the appropriation request, currently system doesnt check the budget also, while saving the approp request.

I have searched for user exits and BADIs, but could not find out the appropriate one.

Can some one help me out in solving this issue.

Regards

Praveen