Gave the above workaround a try. I created 2 custom series Category columns (using column type 'text column for keeping series-like information') in addition to the system Series column already in the application. Plus, added the composite column to show all 3 series columns and each of their respective series index numbers. It displayed correctly in the library view in that I can see all 3 series names and index numbers. However, this does not really accomplish what I was looking for.
The drawbacks I ran into with this approach include:
1) For anthology collections that have 3-5 different stories in it that each have their series, I would potentially have to create up to 3-5 separate custom series columns in order to input each Series name and index number.
2) When inputting a series name into each one of the new custom series columns that I created, there is no correlation to the series names in the primary system Series column. By that I mean, that when inputting a name, I only get a drop-down/category editor list of series names that have been input into that specific column to date. No series names from either the system Series column or any of the other custom series columns appears. That could mean that I potentially end up with the same series name in more than one Series category list...but unlinked to each other. I could not be assured that when clicking on a series name from the tag browser that I would see all the books in that series. Makes Series in tag browser unmeaningful and would have to resort to searches instead to find all books under that one series name.
If I try to workaround that by placing the composite Series field in the tag browser instead, it just shows an expandable list of all the series names with each line having potentially up to 3 series names. For example, it would show "seriesname1 [n], seriesname2 [n], seriesname3 [n]". It does not break the 3 out into each individual Series name of "seriesname1 [n]" , "seriesname2 [n]" and "seriesname3 [n]". Again, that means I could have the same series appearing more than once in that composite list and not being to click on it to see all the books in that one series.
By comparison, what I was really looking for is having the system Series category work like the system Author category. The latter can not only support the input of multiple authors in that one field but when it comes to the tag browser, it will break out and list each individual author separately. For example, if I had Author(s) field in a book set to "Doe, John & Smith, Jane" for a book. The system would automatically list them separately as "Doe, John" and "Smith, Jane" in the Author category in the tag browser.
How would one go about achieving a solution similar to how Author field works for Series?
I tried looking thru the customizable sections of the GUI and plugins. I don't see a way to view the code that controls how Author works. And don't have a way to view/change the code that controls how Series works to match it. It's obvious in my tests on creating new custom Series categories (i.e. User categories) that they are working differently than how the existing system Series category works.