F1 World-Grand Prix Multiplayer-Private session (or solo) Vs iA

I would like to know if it is possible to launch a solo session, in the "Multiplayer Grand Prix" section with AI?

If yes, how ?

If not, why ? : Because if that's the case, it's a shame since we can't train.

Ps: Thank you in advance for answers. If we can't open a solo session, I'm thinking of creating this topic on the forum in the "suggestions" section.