Yes.
It can create the image of "an object, a creature, or some other visible phenomenon". A group of visible creatures is not "a creature", so it's "some other visible phenomenon".
The reason to read this as maximally inclusive is that, since the illusions aren't real creatures, there's no basis to distinguish illusions of creatures from illusions of things that aren't creatures. For example, if you are (arbitrarily) not allowed an illusion of two dwarves, you can define it as an illusion of two illusions of dwarves, and it's the same result.
Or you could imagine a creature whose physical form is two dwarves linked together by an astral silver cord, and make an illusion of that, with the cord of course being invisible. The fact that the creature isn't real is no obstacle; if this isn't an illusion of a creature, then it's an illusion of a visible phenomenon that's not "a creature", and is allowed on that basis.