According to e michael brandt :
Sounds logical to me. Thanks.

[That only applies to the NEC. The CEC _requires_ tied breakers
on shared neutral circuits, period.]

But that's irrelevant. The original issue is NOT whether the breakers
are tied together, but because they share a neutral.

You _cannot_ feed a shared neutral circuit with two separate
AFCI's or GFCI's. It just don't work. Code or not.

You either have to split the neutral (run another cable),
OR, install the AFCI's AFTER the circuit splits to the bedrooms.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.