So I was trying mixmax - the chrome extension and got to know it tracks email open event even though the same mail is sent to multiple recipients and it is able to identify receivers properly. I checked and found that it adds different pixel URLs for all receivers, mail looks same (that's not my concern) but in 'to' or 'cc' all the recipients are visible at receiver side - that's the question!
From receiver end that 'multiple recipient' thing is visible, then how does it send different emails but not separately?
from the sender, this link is passed -
but from receiver these links are visible that gets modified for 2 receivers-