Difference in actual cost of acquisition

dear forum

i bought shares of 6 companies last FY and sold shares of 4 companies.

My question is that while calculating cost of acquisition, should the cost of acquisition of only those shares should be considered that have been sold or the total cost of acquisition in the last FY should be taken into consideration as provided by Groww(my discount broker)in the capital gain statement.

In my opinion, in my case,cost of acquisition of shares of only those 4 companies should taken that have been sold, but the groww STCG report takes into consideration cost of acquisition of all 6 companies.

But again, another doubt arises ..this time i had sold all the stocks bought of any company.... had I sold a partial amount, what should be the treatment then?