Q: What is the best way to (separately) manage rental properties within a company that also provides another service?
A: Add new accounts as needed for the service Business. Add Class for the “service” business and Class for each property. This will allow you to classify all your transaction by class.
Also I would suggest organizing the Customer Center so all the rental properties are together. QuickBooks allows up to 5 levels within the Customer Center.
View your reports Profit & Loss by Class and Balance Sheet by Class.