I need to create a saved search that will return the entity names of those that do not have a particular service.  Here is some sample data:

Entity /  Service
Company 1 / Service A
Company 1 / Service B
Company 1 / Service C
Company 2 / Service B
Company 2 / Service C
Company 3 / Service A
Company 4 / Service A
Company 4 / Service B

If I want to know which companies do not have service C, how do I get that?  So, in the data above, I want it to return Company 3 and 4, but not 1 and 2.  If I just exclude Service C, then I get all four because each of them has a service that isn't Service C.  I tried to write a CASE statement, but I'm pretty new to NetSuite and can't figure out what fields to call and how to get it to return just the ones that don't have Service C.  I've been staring at this for