Combine results of multiple custom dice

If I roll multiples of the same custom dice (for example, 5d[a,b]) it sums the results in an easy to read format: a(3), b(2)

However, if I roll multiple sets of different custom dice with the same symbols, it does not combine the results. For example, 5d[a,b] + 5d[b,c] might give us a(2), b(3) ~ b(2), c(3). Even if the custom dice are the same, the results are split - 5d[a,b] + 5d[a,b] might give us a(2), b(3) ~ a(1), b(4).

This came up in chat today. Someone has a large custom die with a bunch of repeating symbols and an even larger custom die with the same symbols in different amounts. The dice serve the same function, but one is the upgraded version of the other and both are often rolled together. The example below is a roll the game might use.

!(2d[□,✸,☬,✸ ☬,✸ ✸,☬,✸,☬ ☬]cl + 3d[□,☬ ☬,☬,☬ ☬,✸,✸ ☬,✸,✸ ☬,✸ ✸,✸ ☬,✸ ✸,✧]cl)

Result: ☬(2), ✸ ~ □, ☬(2), ✸

The output isn’t awful, but it definitely isn’t as readable as summing the results - ☬(4), ✸(2), □, I suppose.