Covid-19 travel restrictions have prevented Fiji's New Zealand-based coaching staff from travelling to Europe, with outgoing Fiji sevens coach Gareth Baber to lead an interim coaching panel next month.
Cotter said it was a unique situation but they have managed to assemble a team to work with the squad on the ground.
"I got in touch with Duncan Hodge, who was my assistant in Scotland from years ago, Cotter explained.
"Rory Best I knew from my times with Scotland and (in the) Six Nations he was captain of the Irish team, so we used to see each other often. He's now a new coach (and) I knew he could work well with Jason Ryan.
"Duncan worked well with Daryl Gibson and then we always had Richie Gray up there, so those are the three coaches and Gareth (Baber) being up there and having experience with Fijian players became a natural choice."
Vern Cotter and his staff selected a 28-man squad to play Spain, Wales and Georgia, which features four new caps and only players based in the Northern Hemisphere.
He said the two sets of coaches have been in constant communication.
"We've been Zooming. It's like video games - we've been on Zoom calls the whole time, so a lot of information has been exchanged on what we were doing during the July series against the All Blacks, our themes, where we're heading, our points that need to be driven to make this team better with the players we have selected."
The Flying Fijians will assemble in Spain next weekend and Cotter said his team will keep in touch with the interim coaching staff but also give them space to get on with the job.
"We don't want to get into the way either but we will certainly have our views about the matches before preparing for each match," he said.
"It's been an open exchange of ideas whereby we have freely given our knowledge of the team and players and we have offered videos of our past training sessions to continue our themes."
The Fiji players will also play a vital role in assisting the coaching team over the next month, Cotter believed.
"The players themselves are experienced and they will take a lead role in this to ensure there is continuity. They will also have to stand up and take responsibilities as well for the campaign."