How to use 1Password 6 and 7 on the same Mac in different user accounts with different data?

I use subscription 1Password v7 syncing with a 1Password account, my wife uses standalone 1Password v6 syncing with Dropbox on macOS Mojave.

We both have separate user accounts on the same MacBook and I want to use 1PW 7 in my user account and my wife wants to continue using 1PW 6 in her user account. She has a standalone license for 1PW 6 and is not interested in upgrading to 1PW 7 or moving to subscription.

It seems it is not possible to have both 1PW 7 and 1PW 6 running on the same Mac, despite being in completely separate user accounts.

As soon as I install 1 PW 7 in my user account, it zips up 1 PW 6 and basically forces my wife to use 1PW 7, which she can't because she doesn't have a standalone license for it. If I unzip the 1PW 6 in her user account and try to use it, I find that the 1PW 7 Safari extension has commandeered her Safari and doesn't work with 1PW 6. No amount of cajoling the extensions or 1PW apps seems to work.

I tried moving 1PW 7 and 1PW 6 into each users' specific ~/Applications folder, rather than the shared root /Applications folder, but that doesn't work, as 1PW 7 refuses to run unless it is in the root /Applications folder for some reason.

Is there any way of doing what I want (which works fine for many other applications), or is this another way of forcing people to upgrade to 1 PW 7? Not every person who shares the same Mac, necessarily wants to use the same versions of software. The user specific ~/Applications folder should be a way of allowing this.

1Password Version: Latest v7 and v6
Extension Version: Latest for each
OS Version: macOS Mojave 10.14.4
Sync Type: Subscription and Dropbox