That's interesting, I've never heard it put that way. All of the stars in our galaxy are bound to each other via gravity. And they would have similar magnetic fields if they are all rotating the same direction (adding together and making a cumulative magnetic field, similar to two waves in the ocean combining to make one big wave). But over long distances, gravity is much more powerful than electromagnetism. So the force of gravity wins out on large objects like planets and stars. But the galactic magnetic field would definitely have an effect on individual electrons or ions floating around in space, perhaps funneling them towards a certain point, the same way Earth's aurorae funnel solar wind towards the North and South poles.