the orientation cantrip says the following (PHB, 248):
You hit a consenting creature. Once before the end of the spell, the target can roll a d4 and add the number to a capacity check of their choice. He can roll the die before or after performing the ability check. The spell ends then.
The Combination of Magic Effects section says the following (PHB, 205):
The effects of different spells add up while the durations of these spells overlap. The effects of the same spell repeatedly launched do not combine, however. Instead of, the most powerful effect – such as the highest bonus– from these castings apply as long as their durations overlap, or the most recent effect applies if the castings have equal power and their durations overlap.
If there are 3 PJ (Alice the Cleric, Bob the Druid and Charlie the Robber), and two of them know orientation, can they (Alice and Bob) run it on another PC (Charlie, who is about to do a capacity test) so that Charlie can use the best of both d4 rolls, actually rolling the d4 " with advantage "?
Obviously, d4s do not combine; rather, if the Alice d4 orientation rolled a 1 and Bob's d4 orientation got a 4, then Charlie added 4 instead of 1 to his ability test?