Taking a guess here, based on my experience with Customers and Invoices (which I think are not really much different from Vendors and Bills).
I think an account of type Accounts Payable may offer the functionality you want. Note that when you enter a new transaction in such an account, there is a Vendor field. There I think you would enter Office Depot. Also note that in such an account there is the Type column. Click the entry field until it turns to "P", which signifies "payment." With these two pieces of coordinating information in your transaction, I bet your report on the Office Depot Vendor will reflect the Payments.
Having said that, I'm wondering if this is just too much functionality for your purpose. Why not just track Office Depot expenditures with a dedicated Expense account? (Why go to the trouble of maintaining a Vendor?)
My understanding is that Accounts Receivable and Accounts Payable are used for accounts with delayed transaction processing. Ie, for me I have a Customer and when I submit a bill to them our terms are that they have 30 days to remit payment; so I use Accounts Receivable to let my balance sheet reflect payments that I have requested but that I have not yet received.
If you've got a credit account at Office Depot, and you're able to acquire goods from them without immediate payment, then I think you have a good use case for Accounts Payable. However, if you're really just tracking instantly-settled debit-card purchases (that is, if that wasn't just a contrived example), I would suggest a simple Expense account.