TOC to include range of pages for sections

Excellent advice from both @Peter Spier and @Dave Creamer of IDEAS 

You could also do this by building cross references instead of using the TOC feature.

https://helpx.adobe.com/ie/indesign/using/cross-references.html#:~:text=Choose%20Type%20%3E%20Hyperlinks%20%26%20Cross%2D,Reference%20button%20in%20the%20panel.

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https://creativepro.com/creating-cross-references-with-a-page-range-in-indesign/

This may or may not help you...

Back around CS5 days I used to do an annual directory for local antique dealers that included an index to advertisers. Rather than a real index this was a TOC, and it often had more than one entry for some advertisers. Peter Kahrel was kind enough to write a GREP query that I could run at the end that consolidated the duplicates onto a single line and added commas between: ^(.+ )([\d, ]+)\r\1([\d, ]+)$

I expect this could be modified to show page ranges if you can generate a TOC entry for each page.

You could create an index and use it as a TOC.