I've been trying to develop an appropriate workaround for shared neutrals in applications such as furniture feeds, surface raceway, and site lighting and I stumbled upon this post.
@Martin__Schmid, I think that the 'pin heads' in the OP's third example is indicating three separate grounds (one separate ground for each circuit).
To answer your other questions: you are correct about what the NEC requires, and I'm not aware of (nor can I conceive of) any way to do this if the circuits are not adjacent to each other in the panel.
I have an idea for how to support shared neutrals that may be rather simple to implement: expand upon the Group functionality in panel schedules. I came across this help article that said grouping was to support shared-neutral circuiting. Circuit grouping in panel schedules is inadequate support for this, but it did give me an idea.
What if you added two more grouping functions: "Group With Multipole Breaker" and "Group With Handle Tie".
The "Group With Multipole Breaker" function would leave the Circuit and Description as separate lines but would merge the trip and pole rows (depending upon that setting in Electrical Settings). Trip would need to be equal for all three (editable by user) and poles would depend upon the number of circuits merged.
The "Group With Handle Tie" function would group them, but leave them all as 1-pole breakers, each trip editable and can be different (though this is uncommon), and there needs to be some indication of a handle tie. Mere shading wouldn't work because then you wouldn't know which are tied when multiple ties are adjacent. It'd take a little thought to figure out how to show the tie.
In both of the above cases devices would need to be tagged with the individual circuits. Same for wires, unless the wires were connected to multiple circuits. I think that the multiple options for showing the multiple circuits (commas vs ampersands, etc.) could be settings that trigger based on how the breakers are merged, probably with per-circuit overrides.
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This doesn't involve shared neutrals, and I don't mean to hijack the thread, but I can think of two more group functions that could be added:
"Group and Merge": There are cases where a 1-, 2-, or 3- pole breaker can take up more than 1, 2, or 3 panel slots. The most common example is shunt trip breakers. The shunt trip device takes up an extra space in the panel, but that space isn't connected to anything - it's just attached to the side of the breaker. We usually show this with the 4 rows merged in the description column, the circuit still a separate row, and the load still a separate row (but with no load in the column). To do this in Revit currently, I add a space beside the shunt trip breaker, rename it "shunt trip" and group it with the breaker. If the breaker is in slots 1,3,5, usually we call it circuit 1,3,5 rather than 1,3,5,7. But perhaps that should be an option.
Another use for "Group and Merge": Sometimes high-current breakers can take up double slots. So a 3-pole breaker could take up 6 slots. Physically, the breaker is connected to each phase twice. We show this by merging all 6 rows in the description column, but only showing load on the first three rows (so we don't divide the load between the two phase A connections). I don't know that these are still used; I've only seen them in existing installations. If I had to do this in Revit currently, I would just add spaces to three rows and group them with the breaker. If the circuit is occupying slots 1-11 odd, we'd still call the circuit 1,3,5 I think. But perhaps that should be an option.
(I don't know if that pic is actually of that kind of breaker, but it looks like that.)
You can have a similar situation where high current breakers take up 6 slots across from each other rather than adjacent to each other.
"Group With Tandem Breaker": A tandem breaker is a way to get two circuits out of one panel slot. Both circuits are connected to the same phase. I don't know how I would do this in Revit if I ever needed to.
Engineers hate these things because they screw up our schedules. Contractors will often install these to squeeze in another circuit. I can think of a couple of different ways to show this in a panel schedule, but I've already waxed eloquent, so we can discuss later if you like.
Let me know if it helps for this to be posted as a separate idea.