Medium Transport; High Wing; 2 Turboprop Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 9
Communication Breakdown; Confusion; Situational Awareness
ATC Issue All Types; Conflict Airborne Conflict
Air Traffic Control Issued Advisory / Alert; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Took Evasive Action
ATC Equipment / Nav Facility / Buildings; Airport; Procedure
Aircraft X checked in turning back with the number 2 engine out; blocked Aircraft Y trying to check on from approach who was not radar identified climbing to 12000 feet. Aircraft Z was about 10 miles out in front of the Aircraft Y not on my frequency climbing to 12000 feet inside of Approach airspace. When Aircraft Y called initial check on was that he was responding to a TA climb. So I radar identified him and then climbed him to his filed altitude. Immediately after Aircraft Z checked on and advised that someone just flew past him.  I told Aircraft Y that I had no idea what Nassau was doing since it was their airspace but told him to maintain 11000 feet so he would be separated from Aircraft Y. Aircraft Y was on an incorrect code. During this time an aircraft A was 8 miles and parallel with Aircraft Y so I could see Approach was having difficulty separating their planes. Fix the RADAR feed so I can see aircraft departing Nassau. As it is right now I cannot see aircraft below 9000 feet which would have prevented this error.  We did have a radar feed in their old system but since they went to the new system we can't see anything and it is really dangerous. I can't believe this vital piece of equipment was overlooked.
ZMA Center Controller reported managing aircraft conflicts caused by difficulty coordinating with adjacent airspace.