I need to breakdown an account "Contracted Rentals" into 5 categories - can I do that?

Welcome to Community, @drossovich.

Let me share some information about categories. You can create subaccounts to break down your expenses, income, and other account types into more detail. Let me guide you how.

1. Go to Accounting.
2. Choose Chart of Accounts.
3. Tap New. Then, select the account type and detail type.
4. Mark the box next to Is sub-account and then enter the parent account. 
5. Click Save and Close.

With the above steps, you're able to break down your accounts in the Chart of Accounts.

Want for details? Check out this article: Create subaccounts in your chart of accounts in QuickBooks Online.

Additionally, here are some articles for additional resources. Feel free to check out.

• Group your products and services into different categories

• Find help with bank feeds and reconciling accounts.

Please don't hesitate to reply to this thread anytime if you have follow-up questions or concerns with categorizing items or accounts. I'll be around for you. Take care and have a great day ahead.