Question regarding Regional day pass?

Hello,

So me and two others are going to Chicago. According to my planning, we will be taking the metra and then will use the CTA about 3 times during our trip.

I've already have the ventra app and a digital Ventra card on my phone that I've used before while traveling alone and will be using that to cover the metra and bus fare.

From my understanding, I can buy the 3 metra tickets on just my phone for everyone, no problem.

I had read about the regional pass option that shows up after you purchase your ticket.

Would I have to buy a ventra card + a pass for each ticket, or since there is only one ventra card on my account and will be used for all 3 people, just one regional pass will do?

TIA.