You can try holding the bottle in hand and put it near their face. Helps if you press the tip in a bunch of times so they can smell the water on it or it's dripping. After my gp gave birth and was done with cleaning, she was staying in her cubby a long time with babies, and I tried this with her bottle knowing she had to be thirsty and she drank like crazy while I held it at the cubby entrance.
Give them some lettuce, cucumbers, etc., that has a higher water content, so they'll at least have some water until they figure it out.
FWIW, I have 2 day old pups and I've seen one of them already try to drink from it (while hanging). Hay platter (upside down Frisbee) and food, along with a tunnel pipe is all right in the vicinity, so they are running by it constantly. If it was in the opposite end of the cage, they might be less likely to run by it.