Can two LR Account holders share and manage the same photos and catalog

Hi,

First post for a LR Classic newbie.

My wife and I have two separate Adobe accounts. She uses PC, I use Mac. We have all our photos in a home server and I have generated a catalog in my Mac.

1.- Is there a way my wife can now copy my Mac catalog with all the previews etc attached to it, and use it in her PC?

2.- If yes, will any changes implemented by her on her PC-stored catalog or on our photo repository be synchronised in my own Mac-stored catalog and vice versa? For example, if she imports photos or edits existing photos on her PC, will this be automatically "seen" by my catalog on my Mac?

3.- Or the only way we can have a unified catalog and photo repository is to have both in an external HD (as I understand LR does not allow catalogs to be in servers)?

4.- If the answer to 3 is yes, can a single catalog be used indistinctively by PC and Mac?

Hope all questions are clear.

Thank you.

Jose