No, sorry, no "cold turkey" for my mares- far too stressful for both and the mares really DO worry where their babies are.
I also consider three months far too young for weaning- a foal needs it's Mama for far more than just food.
I can take my four month olds away form Mama for long periods of time, hours even and so long as they have each other and food they are happy (they are in sight of Mama though) .
After a few hours Mama is ready to have them back, and getting a little anxious.
The first "batch" is coming up for weaning and soon, one day, they just will not get turned back out.
They will be in the paddock they have been coming into and they will be in full sight of Mama.
After a few days/a week or so, they will be turned out in adjacent fields and will not lose sight of Mama until I sort out the winter grazing.
OK maybe I anthropomorphize a bit about their feelings- but not overly so.
I would rather err on the side of discretion on this one, I am afraid.
Edited to add:
I have been doing this a long time, for myself and others, so Yes, I have weaned "hundreds" of foals in my time!!