Internal check with groovy script to telnet SMTP Port -25

Are you looking for all the collectors to telnet to the same set of hosts or each collector telnet to a different set of servers? For example CollectorA would telnet to Server1 and Server2, CollectorB would telnet to Server3 and Server4, etc? If the latter, you would just add Server1, Server2, Server3 and Server4 into LogicMonitor as Resources. Then create the DataSource which telnet to port 25 on ##HOSTNAME## as coded. Then whatever collector is assigned to each server will do the actual telnet check.

Any particular thing you need to do with telnet to port 25 (smtp)? If you are just checking if the port is live or just get the version header, you might be able to clone and modify the existing "Port-" Datasource. I did not test this though.