This is more a VirusScan than ePO question (Assuming you're thinking about VirusScan). As far as I know you can't exclude by service specifically.
Still, services you are looking to exclude may be tied to a unique process or file, it's just a matter of identifying the objects to exclude.
In other cases the service may be tied to svchost.exe (and a bunch of associated dll's).
Tell us what services you were thinking of and perhaps we can work out what you would need to exclude.
Services are processes/executables. So just get the process, run services.msc double click on the service- you'll see the path\process name on the general tab. Exclude that and you're good to go.
Pring Spooler server = C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\system32\svchost.exe = a lot of core windows servics.