Thanks for reaching out to us. Allow me to help provide some insights on how to correct your sales account by salesman in QuickBooks Online (QBO).
Once you create a product, it will only allow you to select one income account to track the sales. What you can do is track your salesman's sales and use the location tracking feature so you can see all the payments for one location.
To turn on location tracking, here's how:
Select the Gear icon on the Toolbar.
Go to Account and Settings.
Choose Advanced from the left menu.
In the Categories section, select the pencil icon.