Hi nortsandcrosses,
At the moment adding a sub-supplier in QuickBooks Online is unavailable in the current set of features.
In the meantime, you can continue using the workaround you're using to record the Bill and Bill Payments. Just make sure you're using the clearing account to post the payment to the correct bank account and accounts payable.
Also, we'd recommend reaching out to your accountant too to get more accounting advice on how to record the transaction. This is to avoid messing up your books in QuickBooks Online.
You can also check this article to learn more on how to Enter bills and record bill payments in QuickBooks Online.
Feel free to post here in the Community if you have other questions. We'll be sure to get back and assist you.
