It is certainly possible to help guide and induce a genuine spiritual experience, but your friends would have to be open to that. In the 60's The Tibetan Book of the Dead was often read aloud while taking LSD for this purpose. The Psychedelic Explorer's Guide by James Fadiman touches on the role of the guide during psychedelic journeys, although I'm sure more detailed resources exist somewhere. My understanding is the intention of the guide to genuinely help is quite important.