"I ride the Tour for the classification, Nibali goes to the Giro," the Dutchman told AD.
"We will probably do the Vuelta together. Not for the classification, but for the stage victories. Richie (Porte) also goes to the Tour for the classification."
2019 Giro d'Italia runner-up Nibali was just one minute and five seconds off the pace of winner Richard Carapaz, the prospect of the two-time former winner going one better in 2020 proving far too alluring for a team with an Italian co-sponsor.
Porte finished 11th at the 2019 Tour de France, the first edition he has completed since his fifth place overall in 2016. Mollema came home in 28th but had a major victory late in the season taking out the autumn Monument, Il Lombardia.
Tasmanian Porte is once again summering in his home state and will tackle the Tour Down Under in January.
Bernal wants Giro-Tour double
Meanwhile, 2019 Tour de France champion Egan Bernal told Spanish news site AS he wants to race the Giro d'Italia and the Tour de France in 2020.
"Doing both is very complicated," he said, "but if we make the decision we could do it well, although I know it is almost impossible.
"Even so, I am a very open person to go to either Giro, Tour or Vuelta, in the end there are three very important races."
"(On Team Ineos) there is Geraint Thomas, Chris Froome and now Richard Carapaz, and we all have to come up with an ideal schedule in which we feel comfortable and comfortable with the careers and roles we have to do.
"But there is a lot of communication and so far there has been no problem because Chris and Thomas are very easy to talk to."