How did I dispose of the parentheses?

I have these sequences, in TE:
a.b,(c,d,e).f
a.b.(c,d,e).f
a.b,(c,d,e),f

I want to dump the parentheses. I used a bit of algebra noting that the comma is always the lighter weight operator. The way graph strctures are use leads to a natural solution and the results for each are as one might expect from expanding manually. The blocking remains.

In case one, the comma closes a set element and opens another. The inside pointers are set as an independent group, but b points beyond f, in the first case. A sight re-interpretation? I hope not. In the second case, I created a segment that included b with the enclosed segment, because it necessarily binded with the c. The b again points beyond the f. In the third case, c points to f, b points to c.

Anyway, maybe I screwed this a little, but there are experts out there who will fix it. Works ok in the lab.