Apply a Gradient Across Multiple Objects?

First, ensure that a gradient has already been applied to all selected objects. Then go to the Toolbar and select the Fill or Stroke box (depending on whether you want to apply the gradient to the fill, the stroke, or even both). Select the Gradient Swatch Tool (G) and position it where you want to define the beginning point of the gradient. Now click-and-drag across the objects in the direction you want the gradient to be applied. You can press-and-hold the Shift key as you drag to constrain the gradient to multiples of 45°, so that you can apply the gradient across your shapes instead of just in a horizontal or vertical plane. Release the mouse button at the place where you want to define the endpoint of your gradient. This applies the gradient across the collection of objects as though it is a single object. You can now change the gradient settings and it will affect the applied gradient. If you want each shape to hold its individual gradient, but you want to be able to make changes globally, just make copies of the original shape, which will keep the characteristics of the first, and when you make any change to the gradient in use, it will be applied globally to each individual shape.