On Dutch websites it is pretty much confirmed by Verstappen's side there is a multi year deal with just RB and not TR. So it will be more than just a race.
From BBC F1
"We are in the unique position to have all four drivers across Red Bull Racing and Toro Rosso under long-term contracts with Red Bull, so we have the flexibility to move them between the two teams," said Red Bull team boss Christian Horner.
We'll see who is going to last longer, and which future younger drivers will come along to replace the existing ones.