Chips & High voltage: Connected in Series?
If  you put three resistors of the same value in series, then you would get equal voltage division between them.
But chips are not like resistors. Their current usage is not constant and typically vary by orders of magnitude even within each clock cycle. See why this would be a problem?
If you have good 3V batteries that supply 3V up to the maximum current that the chips can draw, and the chips are rated to run reliably at 3V then there is another problem. Maybe you need decoupling capacitors across the chips?