Work together is better than trying to stack orientation
Having tried to add 1d4 to a run with the advantage of attempting to stack 1d4, what you can not do anyway because of the magic effect combination rule you've already quoted.
I did it in a number of situations where my clerk throws orientation on our barbarian and then another of the players provides help that gives the barbarian advantage over the Survival riding (looking for food in a wilderness adventure) or on the athletic roller (in a case where we wanted to make sure we dropped a door).
The average guiding bonus is 2.5 (with a 1d4), while the expected benefit of the advantage is between +3 and +5, depending on the difficulty of the task. (See this question and the answer for a comprehensive treatment of what the advantage is the advantage when it launches 2d20.) What you can expect as an advantage is the + 1d4 of the l & # 39; orientation and another + 4 (+/- 1) depending on the DC of the task.
The character leading the effort – or the one with the greatest capacity modifier – can do a capacity test with advantage, reflecting the help provided by the other characters. (Basic rules, p.62, italics)
Ask Bob to help Charlie after Alice's advice. Charlie 1d4, and ride with advantage.
Warning: Unless both characters master thieves' tools, it will not work with locking locks.
We also combined advantage and tips to avoid getting lost in the jungles / forests of Chult (Tomb of annihilation published adventure) where before doing my wisdom check (Survival ~ Navigation), that of the cleric orientation. I already have the advantage because my favorite terrain is the forest. (That's how the DM rules it.) I can see that another DM would require a different approach (Ranger is helping the hired guide, the clerk is guiding the guide, unless the PC Ranger is at the origin of Cult).