I have finished a tool that can be used to put the first entry headword on the page into the header guide word when exporting using Libre Office. You will need to download and install OdtXslt. It will put a batch file on your desktop called ApplyFirstHeadword. The steps to use it are:
1. Run the Pathway export normally
2. When the document loads in Libre Office, insert a space and delete it (so the file will show it needs to be saved).
3. Use File, Preview pages (to force soft page breaks to be inserted).
4. Use File Save and Exit Libre Office
5. Drag the odt onto ApplyFirstHeadword
6. Re-open the odt in Libre Office
This should make the first headword on the page the guide word for that page. Libre Office doesn’t handle this well. This process allows Libre office to insert soft page breaks. Then it uses their locations to help decide which headword needs to be the guide word for that page. Let me know if you have trouble.
Currently this only works for one file. It can be used if both the main and reversal sections are exported but the process would need to be done for the main.odt and the flexrev.odt and in my experience, the flexrev.odt breaks the pages differently when it is loaded separately and when it is loaded as part of main.odm so this process doesn’t work well for that.