When your furbabies act like this, being loud, pushy, biting, snarling etc they are showing dominance over you. Whether you're coming or going they just won't allow it. Be careful bc I know how 'cute' and 'silly' such a little dogs snaps and barks seem and often times aren't taken seriously. But pretend for a minute that your little yorkie is a bull terrier or a rottie, would you accept the same behavior? Your best bet is to work with them until they come to realize that you're the 'top dog' and you can come and go as you please. And also try and remember, that when a dog acts like this the dog is unhappy. A happy balanced dog is calm, relaxed and respects your boundaries. It's difficult work for a dog to hold the leader position which is why we all should do them a favor and be the pack leader