Whenever me and my friends play minecraft in multiplayer, the nether portals connect to one portal in the nether, you go through them again and it's one overworld spawn in another person's portal. 

What i expect to happen: i go through my portal into my own spawn and then go back through and come out through my original portal.

What happens: i go through my portal and come out in someone else's spawn, the go back through and come through their portal in the overworld.