Every query is a query which means you can build the query to the results you want to get or not get. You have multiple filtering options that allows you to exclude/include certain results. Some of the examples are:
| where Computer !in~ ("Computer1", "Computer2")
| where Computer != 'Computer1' or Computer != 'Computer2'
Or if they start with specific prefix:
| where Computer !startswith "Computer"
Pick whatever serves your needs.
You also have the possibility to build a function: