I have a customer with at TA1232 and TVS90 that we do something similar. Our ring groups are 19x (your phantom lines). We use these ring groups extensively. In fact, I replaced the TA1232 with a TA824 and pulled it out after 3 days because the 824 didn't support ring groups.

First, a specific extension can only belong to one ring group so if you have an extension as part of 281, I don't think it can also be part of 280. It sounds like you are trying to set up extensions as part of departments and operator, which I don't think you can do. Again, I'm talking from the perspective of the TA1232.

-Ken in MD-
www.kyawacomm.com