There is no built-in functionality for this. This feature is on our customer wish list, but we do not have a release date for it at this time.
If the computer names follow a specific format, you could use % as a wildcard. Submitting LAN% excludes any machine whose name starts with the word "LAN" for instance. This is not something we can provide instructions or support for, but you could also insert the exclusions directly into the relevant database table, which is tsysdonotscan. You could use SQL Server Management Studio for this or execute a script in the Lansweeper web console under Configuration\Database Scripts. Just to be safe, back up your database prior to running any scripts, by following
these instructions.