You would be using Class Tracking in QB, for Departments, Divisions, etc. Then, you assign each person to their Class, and that tracks P&L by Class for you. Make sure to include Class Track Expenses = the employer's share of taxes also get allocated By Class. You run P&L by Class to see the Columns. You can also show someone has One Payroll Item, such as Hourly, but list it more than once = reiterate and "class track per earnings item" to show their Hourly Pay falls into more than one Column = Class.
Not More Pay Items and not More account Rows.
I have an attached image that shows a QB file which was micro-managed as you are asking to do, with more and more pay items and more and more accounts. Once we Enabled Class tracking, you clearly see that the Employer's Payroll Expense is One Row, allocated just fine.