Martin,
In my opinion, and the OP would have to elaborate his meaning,
1,3,5 is indicating a 3-pole breaker. 3 Hots + 1 Shared Neutral.
1&3&5 is indicating 3x 1-pole breakers. 3 Hots, each with their dedicated neutral
1+3+5 is the same as above, but each with a dedicated ground.
If I have single pole breakers and I know I'm sharing neutrals, then I want to specify commas as a circuit separator.
If I have a 3-pole breaker for single-pole circuits, then I need Revit to support that.
In any scenario where I have a 2-pole or 3-pole breaker, I want to use dashes as a circuit separator.
Furthermore, if I am combining multiple circuits with shared neutrals into a home run, then I want to clearly distinguish those, and wiring should clearly indicate that as well.
Circuits 1,3,5 & 7-9-11 is using 2 neutrals, but I prefer those neutrals to be shown next to their respective circuits. See attached (below?) image for reference.