[onewhippedpuppy]

Could you rig something up using a bottle with a pump? Think soap dispenser. One pump would dispense a roughly consistent amount. If you want bigger they make pumps that install into oil bottles that are used for filling things like differentials and boat outdrives, they have a hose attached that might be easy to hook up to a nipple on your dishwasher and could definitely pump a rinse aid upwards.