I have a SL1100 that is setup to use a ring group. Everything works great most of the time. I have 1 issue that I just cannot seem to solve. If an extension is active and another call comes into the ring group the active extension cannot pickup the incoming call. You can hang up or put the other call on hold and you still cannot pickup a second call. The only way to answer is to go to a different extension. I am sure I am just missing something but I have been unable to find a solution.

Try using loop keys instead of trunk keys. You will probably also need some park keys.