ZID CTLR EXPERIENCED OPERROR AT FL280 DURING BUSY; COMPLEX TFC PERIOD AND DE-COMBINING POS.

Narrative

I RELIEVED A TRAINEE AND INSTRUCTOR TEAM AT LOU SECTOR WITH MYS SECTOR COMBINED. THE TRAINEE WAS SLIGHTLY BEHIND AND SEVERAL THINGS NEEDED TO BE ACCOMPLISHED QUICKLY. ALMOST IMMEDIATELY AFTER TAKING THE SECTOR; THE ASIC ADVISED US TO SPLIT THE MYS SECTOR. THIS CREATED SOME CONFUSION AND THE AID OF THE RADAR ASSOCIATE CTLR WAS NEEDED. COMPLEXITY WAS INCREASING DUE TO THE MULTI-TASKING OF SPLITTING AN ALREADY BUSY SECTOR AND TRYING TO 'CATCH-UP' AN ALREADY BEHIND SECTOR. AT THIS TIME; IT BECAME APPARENT THAT THE MYS RADAR CTLR'S HEADSET HAD FAILED. ACFT #1 WAS ISSUED A VECTOR AT FL280 TO FACILITATE A HIGHER ALT. ABOUT THIS TIME; AND WITHOUT MY CONSENT; MY RADAR ASSOCIATE CTLR LEFT THE SECTOR TO AID THE MYS RADAR CTLR. I INTENDED TO CLB ACFT #1 AS SOON AS THEY CLRED OVERHEAD TFC. UNFORTUNATELY THERE WAS EVEN GREATER DISTR AT THIS POINT AS MULTIPLE ACFT WERE CALLING; INCLUDING THOSE RETURNING FROM MYS SECTOR; I WAS RECEIVING ADDITIONAL LANDLINE CALLS DUE TO THE ABSENCE OF MY RADAR ASSOCIATE CTLR; AND THE SECTOR WAS STILL NOT 'CAUGHT-UP.' ACFT #1 WAS LEFT AT FL280 TOO LONG AND CONFLICTED WITH ACFT #2. I BELIEVE THAT CA AND OEDP ACTIVATED AT THE SAME TIME AT WHICH POINT ACFT #2 HAD ALREADY IMPLEMENTED A TCAS RA.