Dell AIO scanning: How to remove inactive computers from list

When I want to use the scan function on my Dell 948 All-In-One printer, I have to browse a list of computers on my printer.

However, I want only 2 of the 6 computers to be listed. The rest of the computer names are not used anymore. I am using an internal Wireless card for scanning and printing from multiple computers.

How can I delete computers from the list on my Dell printer?