I have an item (book) with several attachments - each chapter in one pdf. Only the first added attachment is shown in my online library and also only the first attachment's annotations are imported into obsidian via better bib tex. I located the item's file and found that there is only the first added attachment, all the others have individual locations. I tried to merge the pdf to avoid this problem but the pdf is restricted (I downloaded it via my Uni access).

I hope there is an easy solution to this problem. Thank you in advance.