From Point of Sale, you can sell the items also to other staff members with different prices. First, go to Item Manager under Manager menu.

Go to Sales tab and open an already existing item or create a new one. 

In Edit Sale window, you can set different prices for guests and for staff members, in multiple currencies.

By choosing an account in "Assign by default to" you choose a default account for sales for staff members.

In Point of Sale, in order to sell an item to a Staff Member, select it from the list and then click on Sell to Staff button (choose the staff member you sell the item):

The system will ask you then for the confirmation of the sale:

The sales to staff will be visible in Accounts and Transactions under category POS Sales: