My friend gave me a funky laptop batter pack(he says it doesnt work right. I havent tested it yet but i shuold have before posting

). I ripped it open and it has 9 cells. first 3 are wired in parallel, as are second 3, and third 3, then the 3 "clumps" are wired in series. Its 11.1V at 5700mAh li-ion Gateway 600YGR, but if i take out 3 batteries, it will only be 7.4V. I want to do this, but it has a pcb attached to it and all 3 "clumps" are wired in different places.
How can I remove 3 cells and keep it working correctly?
Sorry for no pics, but I will post some later. I just wanted to see if anyone could tell me from previous experience.