# Constant Current IC Driving a String of ICs

I have been having difficulty wrapping my head around the ideas of constant current and constant voltage. Basically I have assembled this circuit with an arduino.

Now, imagine that I wanted to power a different number of LEDs on each pin.

1 LEDs for Q0 | 3 LEDs for Q1 | 5 LEDs for Q2 | 7 LEDs for Q3 and so on...

Now, in the past, I just wired each of the resistors in parallel and then attached their own individual resistor. And that of course worked fine. But I don't want to use so many resistors.

Presently, I have stumbled upon the idea of the constant current LED driver. Such as this one. Now, my question is it is possible to use a Constant Current LED Driver to light different numbers of LEDs on each pin and have them light up with the same brightness. If this is not possible is there some other way that avoiding the use of resistors would be possible? Adding transistors?

Overall, my question is if I can get around using resistors to light up a string of LEDs. My project has quite a few LEDs in it, and being able to eliminate the resistors that go along with them would be a great improvement.