The move will mean players will also have to persuade former Lions coach Andy Robinson and Glasgow's Sean Lineen that they are worthy of wearing the Scottish jersey just six months' out from the third Lions tour of the 21st century.
"I believe it's important the men who see the players on a daily basis are involved in selection," said Hadden, who recently appointed former All Blacks captain Mike Brewer and ex-Ireland assistant Graham Steadman as forwards coach and defence coach respectively.
"I will also be tapping into Sean's intimate knowledge of New Zealand rugby and making use of his experience in that regard during the Autumn Tests.
"Sean will also be involved as a specialist coach, much like Duncan Hodge, our kicking analyst, during the Autumn games."
Hadden had already selected a 50-man squad for yesterday's training session at Murrayfield, although that number was reduced to 40 after his English-based players missed the gathering after the intervention of the Guinness Premiership's governing body, Premier Rugby.
Jason White, Rory Lawson, Scott Lawson, Alasdair Dickinson, Alasdair Strokosch, Sean Lamont, Euan Murray, Rory Lamont, Stephen Jones and Gordon Ross were all absent for Scotland's first get together since their summer tour of Argentina.