More then 10 numbering level wityh a Master Document

Windows 10, LibreOffice 6.3.6.2

I have a master document that put together multiple files, each file having its own numbering style. The Laws, numbered Article 1.2.3.4, the annexes, identified by a letter A.1.4.5 or B.3.4.5 and guidelines, identified with roman numerals, II.1.3.4.5 , To total number of levels being greater than 10. About 80% of the files would not exceed the 10 levels limit, but those who do are very important

When all parts are putted in the master document, an ADM file, the numbering scheme of the master document override the numbering scheme of the individual .odt files. I would like to preserve the numbering scheme of each individual file and generate an index that reflect that. Can it be done?

My primary problem is that this forces me to fuse multiple pdf files and to adjust the index manually, The former being the worst problem because it disable the LibreOffice mechanism that enable the first page of each paragraph to be a right page and forces the manual addition of white pages.

Precision: there are 245 pages in 19 chapters. The book exist since 1997, but it is constantly adjusted to changes in the Laws. It is impossible to know if all chapters decent from the same template. But that would not be helpful because of the 10 levels limit. Chapter 5 to the last chapter are easily handled with a single master document because, together, they do not use more than 10 levels of numbering.
The chapters are number with the tool-> chapter numbering technique. Each chapter has a first page, a left page and a right page for proper margins (larger margin on the binding side).

I have made progress. The Laws uses 5 numbering levels in the form Chapter 1 Article 1.2.3.4, the Annexes uses numbering level 6 to 10. This leaves only the Guidelines out of the numbering scheme. Correction, it does not work because Articles requires 6 levels and leaves and insufficient number of levels for the Annexes.

Thank you in advance!

Your description does not give enough information to understand your issue and suggest a solution. So, please, edit (= modify) your question. Don’t add a comment as it is better to group all needed information at a single place.
Start with general data: OS name, LO version and save format (.doc(x) or .odt).

Most important: how do you format your document? With styles or manually? Styles are the only reliable way to manage complex or large documents. Since your problem seems to be related to numbering, do you use list styles or Tools>Chapter Numbering? Are these numbers applied to “headings”, usually styled Heading n, intended to build a TOC among others?

You mention a master document. Is it a “technical” master with extension .odm referencing sub-documents with ordinary .odt extension? What is the total size of the finished document (in number of pages)? The use of the master+subs may not be necessary.

Since you spread your book across several files, do you use a template (with extension .ott) to guarantee formatting consistency?

Last, what are the specificities of the paragraphs where you’d need more than 10 levels? Are they in fact a list inside a “chapter” where you want to number your items with the chapter number+list item number? But anyway this makes text quite difficult to read. Do you want this full number entered into the TOC too? There are alternate ways to do this, e.g. in a “table of lists/clauses”.