Customization needed in profit and loss statement report

Hi Team,

I created Closing stock and opening stock accounts.I need a customization like when i select filter periodicity quarterly, it is adding 3 months data and displaying, but i want if it is opening stock it should calculate only starting month of that quarter ex:Apr-June it should calculate only april month data
If it is closing stock it should calculate last month of that quarter
ex:Apr-June it should calculate only June month data like for other quarter also.
Only for these two accounts i need customization.Please help me.
Thanks,
Jyoti