It is really a shame that Writer presently allows only one alphabetical index.
A user index is some form of a TOC where entries are listed in page order and identical entries are not merged, thus really creating a TOC.
To the best of my knowledge, there is no way to convert back from a user index to an alphabetical index because the keys (data) are not the same. There is more sophistication in an alphabetical index than in others.
But you can cheat Writer, provided you haven’t used yet the three levels for the keys. The trick requires that you review all your index entries.
- select the word to enter in the index and
- accept the Entry or enter the desired one
- in 1st key, enter Place or Landowner (more specifically what will be the heading of your “index”)
Create the alphabetical index. You’ll get two distinct sub-indexes. To format it as apparent independent indexes, customise paragraph styles Alphabetical Index 1 and Alphabetical Index 2. You’ll probably also want to change the layout of the sub-index headings (to get rid of the leading line at least). To do this right-click in the index and
Edit index and go to the
Entries tab to modify the Structure & Formatting Structure line for levels 1 and 2.