The phrase "agree upon whether" is correct and usable in written English.
It can be used when discussing the need to reach a consensus on a specific issue or decision.
Example: "We need to agree upon whether we should proceed with the project or not."
Alternatives: "come to a consensus on whether" or "reach an agreement on whether".
Nowadays, in Spain, parents can agree upon whether it is the mother's or father's surname that is given to their children, but if parents do not reach an agreement, it will automatically be the father's surname that is inherited by the children.
Also agree upon whether a single person will be doing majority of the writing, the band will all write together, etc. Ask all band members to bring lyrics/poems they have written to practice, but be prepared that you may write new ones whilst there.
Sure, there are always going to be debates about antitrust doctrine, but in principle, our antitrust laws have worked well, and that is agreed upon whether you're Milton Friedman or Judge Posner or someone far to the left of either of them.
Some such claims are widely agreed upon: whether we write from left to right or right to left, for instance, and what particular marks we choose to represent words on paper.
It is also not agreed upon whether Mussie is a single creature or a species.
That is something we should all agree upon -- whether you are for or against nuclear power.
What they can't agree upon is whether farm policies make food too cheap or too expensive.
In Washington, almost all the action is about whether the Congressional Super-Committee will agree upon another $1.2 trillion in budget cuts or whether they will be imposed by fiat.
It remains to be seen whether the Court can agree upon such a theory.
Some specific plans required all co-authors to discuss and agree upon the meaning of the plan and whether our interview items were sufficient to measure achievement.
Make sure you agree upon the size and shape of the vessel, whether he wants it to be a spherical or cylindrical shaped vessel.
