Candi,
I know this is an old post; however, I have a similar workflow for organization charts in the AEC industry.
I use a fixed value for my organization charts. You can apply the following grep expression and James Fritz’s guide an on percentage based styles to get the desired result. https://creativepro.com/creating-percentage-based-styles.php
I will assume that the name, title, and post-nominals are on one line and each individual has a separate text frame. Add a Grep Style with the following expression:
,.+
Your associated character style could be a fixed value or it could apply the aforementioned percentage based styles described in James’ guide.
In regard to removing the first comma, physically removing it would require a grep find/replace. I don’t think that InDesign’s grep has the ability to match the first instance only. If it did or if there is an expression that can do the same, you could then hide the character. A character style with horizontal scale under the advanced character formats set to 1 percent and the fill color set to none will make the character invisible. My first thought would be to do a Grep Style that looks for all commas that are not preceded by a comma anywhere in a paragraph. Lookaheads can have expressions; unfortunately, lookbehinds are fixed. A grep guru might be able to assist.
Definitions
, A comma is a literal value
. A period refers to any character, including a white space character
+ A plus sign indicates one or many of the previous character
.
