An honest question should not be downvoted... You're correct: on the large scale of the universe, everythings seems to drift apart, like a helium weather balloon floating up in the sky pushing individual heliums atoms further apart as the balloon grows in size. These helium atoms still bounce against eachother though, but that frequency drops as the balloon gets higher up: the internal pressure drops. It's just that individual helium atoms have speeds greater than the speed with which the balloon extends.
It's the same for stars and star systems: if their individual movement is with higher speed than the speed with which the universe is expanding, that individual movement will prevail.