You and a few of your friends can’t choose for them? You can’t cancel their citizenship
But, isn’t that what Washington, et al. did when declaring independence from England? Declare everyone in America to be citizens of America?
Not in one step. They were colonies that declared their independence as new states. Then the states created a confederation. Later, "we the people" of the United States, "in order to form a more perfect union," drafted and ratified a Constitution.
However, you're correct insofar as the Declaration of Independence declared the colonies to be free and independent states and the citizens of those new states were undoubtedly viewed as citizens of those states by the people who recognized the declaration. Ultimately, by winning a war for independence, everyone recognized the new status.