Nesting rules and substitutions (ex: "open links X with app Y replacing Z with W")

[Mateo-EBA]

Being able to nest rules and substitutions would greatly amplify the potential uses for the app.

For example, if I open a link for google meet from slack, I want it to open with a specific google account user.

Currently I can either redirect ALL google meet links to that specific user, or redirect all slack links to a specific browser.

For this use case to work for me, I would also need in the substitutions the option to "append" instead of "replace", so I could set something like:

• [Browser] Vivaldi
  • [Rule] Title "Slack"
    • [regex]
      • [find] "https://meet.google.com/.*"
      • [append] "?authuser=3"

Which, in words, would be "to all urls opened from slack and starting with 'https://meet.google.com/', append '?authuser=3' at the end".
That way it would work with any meet call path (without "append", if I had to use "replace" I would have to set a rule for each google meet path).

I know the usual recommended way to deal with something like this is use a separate browser for work with the work google account as default and redirect all slack links there... but I want to have access to all my bookmarks and stuff from other accounts on the same browser