Creating Document links in LO Writer with AltSearch

I use the excellent AltSearch extensively with LibreOffice Writer but I am having a problem that I can’t solve.

I have a document that has a lot of file names within it and I need to convert them to relative document hyperlinks so that I can click on the file name in the pdf formatted version of the document and be taken to the corresponding file,

I am attempting to use the /h{url) in altsearch to create a link but it always creates an absolute Internet type link even when used with file://
To have LibreOffice save relative links I need to create a document link.

Can this be done with AltSearch?