I promise you it will NOT work.
Let's try one way to do it. Let's say you put the BC0 lead on the most negative terminal, and BC1-BC4 on the positive terminals of your four cells. Now you still have 4 balance leads. Where do you put the next one (BC5)? I suppose you could put it back on cell 1. Then you would put BC6 on cell 2, BC7 on cell 3, and BC8 on cell 4. If all of your cells were balanced at say 3.25V, balancer would be trying to see 8 cells. It would see 3.25V for the first 4 cells. For the fifth cell it would be measuring relative to cell 4, but what it would see 9.75V (3 x 3.25V) LOWER than cell 4. So the balancer would see these cell voltages:
1: 3.25V
2: 3.25V
3: 3.25V
4: 3.25V
5: -9.75V
6: 3.25V
7: 3.25V
8: 3.25V
My guess is that the balancer would simply burn out, but in the best case it would be trying its hardest to move energy to cell 5 from everywhere else.
Go ahead and try to find some other way to wire 4 cells and make it look like 8 to the balancer. It can't be done.
You are certainly welcome to try it to prove it to yourself, but I hope you don't try and sell it afterwards.