Profit & Loss Report

Warm welcome, @Forest Gal. Let me provide a report wherein you can see your customers and vendors in one report.

Please know there's no direct feature to see all lists of customers and vendors in a group.

Let's pull up the Profit and Loss Detail report to show the vendor/customer associated with the transactions. 

1. Go to Reports, then enter Profit and Loss Detail in the search bar.
2. In the Report period dropdown, choose your preferred date range. 
3. Click Customize, untick unnecessary columns, and make sure the Name is selected.
4. Hover over the Filter and choose All in the Vendor dropdown.
5. In the Customer dropdown, choose All, then click Run report. 

Export the report to Microsoft Excel and group them manually by customer and vendor. 

Moreover, you have the option to memorize the reports you've customized. This way, you won't have to do the customization process again. 

You can always return here by tapping the reply button below. I'd be available to assist if you need further information on what report you can generate in QuickBooks Online.