Best answer by Hikari
As of today you are correct. ID Mobile is working on bringing multiple numbers into one dashboard and that might be available in the future.
Just to make you aware, iD Mobile is allowing only 2 contracts per person where second contract can be taken after around 6 months of the first one. You have mentioned that you would like 3 contracts under your name but if you decide to go for it you would need to ask someone else to take on 3rd contract.
I am hoping that iD will bring family packages at some point in the future as well.