No they don't sense each other or teleport (at least by choice anyway)
Like I said, when the Pokemon is captured, it registers the data to the other pokeballs
Then if the balls register 7, the last captured will go to the PC.
Your pokeballs are registered to each other when you buy them most likely to share the same code by seeing your trainer card, the cashier will scan them and activate them, like a credit card.
If you have any questions PM or VM me, glad I could help!
PikakittenX, devout member of the Pokecommunity