The Royals have benefited from the services of Stoke's Griffin and Blackburn's Khizanishvili, plus Chelsea defender Ryan Bertrand, as they mounted a late push for the play-offs in the Championship.
Those hopes are now over after Tuesday's 2-2 draw at Scunthorpe and McDermott now wants to look at the futures of the three loan stars.
"If I get the opportunity to bring them in permanently then I would love to do that," McDermott told Sky Sports.
"I've spoken to both Andy and Zurab about how things are going and they are happy here at the moment.
"We've also got Ryan Bertrand here, on loan from Chelsea, and if we could keep him for a period of time then I would do too.
"It's a bit early for that really, but once the season is done and dusted then we will sit down and assess the options and take it from there really.
"They are all good lads that have fitted in well, and have done really well for us this season, so if there was any chance of bringing them back next season then I would take it."
McDermott's introduction as manager in December has seen a huge turnaround in Reading's fortunes, as he steered the Berkshire outfit away from the relegation zone and into late contenders for the play-offs.
However, he is not surprised by how well they have done this season despite the lowly position they were in when he took the reins.
He added: "It hasn't surprised me a great deal how well we've done this season because I always thought that we had the players to do so.
"Obviously, we've brought a bit more experience in, with Griffin and Khizanishvili on loan, which has helped and we felt that we needed that to stabilise us a little bit.
"We've got goals all over the pitch though, with both the wingers, strikers and other midfield players weighing in with their fair share.
"I feel that is what you need to do well in this division, with a bit of experience plus a fair amount of goal threat."