Can we build our accounting tree structure on QuickBooks depending on four sides , we are broker (customer , provider , payment gateway or BNPL gateway , us) ?

Hi there, @ahmedelawady-bok. Let me get you pointed out in the right direction to help you integrate your payment gateways in QuickBooks Online (QBO). 

I recommended posting your concern on our separate online forum named Intuit Developer Community. This is a platform dedicated to product developers and website integrations with QuickBooks. 

This site provides software development information as well as the opportunity to ask fellow developers questions. Our Intuit Developers can give you the necessary codes or data to link your payment gateways or BNPL gateway with QBO. Here's how:

1. Click the Intuit Developer forum link.
2. Then, scroll down and select Contact us under the Intuit column at the right pane.
3. Choose QuickBooks Online.
4. Select the Ask a Question button.
5. You may need to create Intuit Developer Account to proceed or simply sign in if you have an existing one.

You may also find the following articles useful that talk about processing payments for QBO transactions:

• Enter bills and record bill payments in QuickBooks Online

• Record invoice payments in QuickBooks Online

Visit our QuickBooks Help page for more guides, articles, and resources to help you with your QBO tasks. It is divided into different categories, which you can browse depending on your concern. When you find one, you can bookmark them for easy access and use them as a future reference.

If you have any other QuickBooks concerns, feel free to post again here. I'll be always around to assist you. Take care.