Multi tenant in Firestore

Question

Looking to build a CRM type application and need to separate the data for each client in the firestore database.

Whats the best way to structure the data?

If we take a few basic collections for this example... company, user, account, product.

• A user is simply the user of the application i'm building.
• This user would work for a company that employs them.
• The user would then look to sell products to accounts.

Generally to handle this should I be placing

• company at the root level.
• Then user, account and product underneath company.

Im unsure whats best security wise and/or normal convention.