There are two things I would be looking for here.
One is a specific claim. At the moment, I am not sure what "same hallucination" means. Many themes emerge from the studies of dreams (falling, flying, running late, unable to escape, etc) and delusions (believing you are Jesus, Napoleon, etc.) Is that the same as the "same hallucination"?
The other is a notable claim. You mention an esoteric book, which is probably popular enough, but you don't actually quote a claim from that book.
If you can pass those two hurdles, then asking "Can different people share the same hallucination?" is on-topic.
See also: Is shared dreaming possible? - but it isn't a good example of a good question.