There is virtually no connection between Quicken's Business features and its Rental Property features. They are nearly walled off from each other.
There's basically no such thing as a Rental Property Business in Quicken.
A Quicken "business" entity reports taxes using Schedule C. A Quicken "rental property" entity reports taxes using Schedule E.
You don't "link" tags to Quicken accounts; you just assign tags to transactions. How you utilize the tags is mostly up to you. But a few tag types do have special properties:
Most Quicken Business features use only Quicken business transactions. A Quicken business transaction must either be assigned a Schedule C tax line item, or be assigned no tax line item and have a Business tag assigned.
Most Quicken Rental Property features use only Quicken rental property transactions. A Quicken rental property transaction must either be assigned a Schedule E tax line item, or be assigned no tax line item and have anQuicken Rental Property tag assigned.
Transactions that are not Business transactions and not Rental Property transactions are Personal transactions.
You may, if you choose, record business transactions in Quicken accounts designated as Business accounts and Rental Property transactions in Quicken accounts designated as Rental Property accounts. But that is not a requirement, and it provides no particularly special results. Business and Rental Property transactions can be recorded in any Quicken account; whether the transaction is Business, Rental Property or Personal is decided by the previously stated rules.