Animating separate parts of a single mesh.

Is there a way to animate several disjoint parts of a single object without using bones? For example, let’s say I have one object that has multiple spheres - I want to be able to move animate those spheres separately (e.g. one moving up, one moving down, one moving sideways, etc.) without using bones. Any ideas? I’m using this for a game which is why I want to keep it as one object (I already know how to animate multiple objects without bones).

you could use hooks. ( ctrl H to add hook to selection in edit mode )