Follow up: Look like the analog line will ring if set to the ring group number for group 601 ("2") in 1802 but not if set to "0".

Digital line all seem to ring for 601 when set to Ring Group "0".

Looks like the proper question may be "how do you assign extensions to multiple ring groups?"

I believe some extensions are set to multiple ring groups but I do not see how to do that from the 1802 section.