I recently replaced a Partner with a Merlin Magix. It is a rel.4.0 The system has 1 TDL card and 4 16-ETR cards to run the old partner Phones. The 2nd cabinet has an LS/GS card and the Merlin messaging 6 port card. When the lines get busy, we have a problem where an answered call can't be transferred. The transfer button and direct voice mail button both become temporarily ineffective. Is there something I need to add to the config to accomodate that many ETR cards? Also the system is in key mode, if that matters. Thanks in advance for any advice.