Indexing paragraphs/sections instead of page numbers

Hi everybody!

I'm working on a law book and have a list of words my client has given me. I have to feed it into Indesign's (mediocre) indexing function. The problem is, I have to create an index with these words, but instead of page numbers (or in addition to them) I need to somehow reference to sections (as in legal code) and paragraph-numbers which I have placed outside the text-paragraph with a text-anchor to the specific section.

Is there a way to use a character format, cross-references as substitute for page numbers? I've been searching the web for days now, and can't find a solution.

Is there any way to do this semi-automatically, or do I have to do create these sections manually? If so, using cross-references, I'd have to adjust section and paragraph-number every time I update the index … that would be suboptimal.

I've already tried IndexMatic3 and some other scripts, but they all seem to just support page numbers instead of these custom variables (or maybe I'm just not looking correctly). I've also looked at Framemaker, which seems quite capable, but it's a last resort option, as our version is ancient and has compatability issues. I've also found software specifically made for indexing (like macrex, index manager, cindex), but I can't really find anything recent on them and can't check if they have these features.

As example, I've attached some pics. Example 1 shows the main text, green is the paragraph number, blue the section number and red what I want as index-marker/-entry. Example 2 shows each part of the index with the same colour code.

I've asked for help in some Indesign/Design forums, and they mostly told me scripting could be the best way to conquer this problem, and pointed me here to ask the pros. If someone who can script can help out in any way, I would be grateful.

Cheers