ICAI Policy in passing PCC students

I am a PCC Student having already passed ACCA UK & CIMA UK Advanced Diploma in Management Accountancy, I had appeared only for Group 2 of PCC in June 2009. I got marks way below my expectations i.e. 30 marks in costing while I expected 60 to 70 marks.

I want to know whether the institute discriminates students who appear for only one group at a time and those who appear for both groups at the same time.

Also whether there is any policy with the institute to pass only specified number of candidates, irrespective of the actual performance of the candidate.