The problem

After linking my zetero account to my overleaf account according to this page, you can only import the zetero library references to overleaf as a .bib file, not groups.

Solver

It can be done with the import from external weblink in overleaf:

Specified group settings: Public: Closed Membership Group Library: Anyone can view, only members can edit

You can hit the zotero api to fetch the bibfile for a group using something like this:

https://api.zotero.org/groups/2501167/items/top?format=bibtex&style=numeric&limit=100

Replace the group id: 2501167 with your own, finding the id is a bit obscure, click your group setting should be able to see it in the web address.

In overleaf when creating a new file you can specify an external url. Use the one above. For the name use something like “references.bib”.

More discussions and details can be found at this pagehttps://forums.zotero.org/discussion/77185/how-to-link-zotero-private-group-with-overleaf