It’s just theorycrafting, but i don’t see why it would not work. Maybe i even change my setup accordingly 
In principle you have one vault just as you have now. Within this vault you have 3 sections: 1. private 2. office 3. shared data.
Unified Vault
├── private/
├── office/
└── shared/
You could use a software that selects parts of the unified folder and mirrors them to some different folder. Last i checked you could not have multiple vaults at the same root-folder while ignoring parts within it. But maybe someone came up with a plugin for that 
That’s why i suggest this solution.
This gives you these two additional vaults/ Folders:
Office Vault
├── office/
└── shared/
Private Vault
├── private/
└── shared/
I love syncthing for that task. It mirrors data between two different folders. Doesn’t matter if on the same or different machines. If they’re on different machines, i think they have to be in the same network. But possibly different networks should work with some setup aswell.s
The shared folder has stuff like:
- .obsidian (plugins, themes, snippets, hotexys, templates
- templates
- shared files (for example a zettelkasten that is used in both contexts as a reference)
- to-do lists
- …
You will have to exclude some files though:
- workspace.json (never ever sync this if you have different vaults. It’ll fuck up the interface)
- workspace-mobile.json
possibly also
- plugin cache folders
- graph cache
- transient UI state
This makes a split: the logical vault != physical vault.
This way you can work in your unified vault just as you did before. The other vaults get the data they need automatically
The “office vault” gets copied to your office cloud via nextcloud, google drive, one drive or whatever. Your private stuff never touches that cloud. You could technically set it up on different machines:
rasperryPI/private: unified vault
office-machine: work vault
private-machine: private vault
This way your office-machine never gets private data and the other way around. That might actually be important regarding data-security.
Some things to consider:
- The mirroring of the folders can lead to sync-conflicts, if you are working at different vaults on the same files at the same time.
- Editing a file while a large amount of files gets synced might lead to a conflict (assuming the file is part of the big group)
- Links:
- Image having one file in
/private that links to a file in /office. While you are in the unified vault, it does not matter. But if in the private vault it just points into nothingness. I’d make it a iron rule: If something is touching both private and office, it goes into "shared” and it avoids linking to either /private or /office. My recommendation would be to just work in the unified vault habitually. And if for any reason (for example a different work-machine) you have to use your office-vault, you just don’t click on orphaned links. Because this would lead to sync-conflicts.
- It’s also important that the root of all vaults is at the same level: example:
/shared/template/daily-todo.mdhas to be the same in each of the vaults. Basically: Don’t let the segmented vault point it /privat/, but at / (root of the unified vault)
- Indexing might be troublesome.
- Some plugins might not work
- Some Plugins index the vault whenever it is opened. Don’t switch often between the vaults
- The Search might return weird results in the “small vaults” regarding backlinks, if you don’t watch out regarding the link-issue mentioned above.
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Alternatively you could just use symlinks. But that’ll likely cause more trouble. Especially on windows. But you have no sync-conflicts, and duplications.
