Need clarity | Creating UNSAccountB from account definition on employee creation

Hi fellow experts,

I hope everyone is save and healthy.

I've configured an account definition for a custom target system and mapped it with a business role (assigned using a dynamic rule). So the creation of UNSAccountB is happening and using the generic script I'm able to provision the same in the Target System.

However, I would like to configure the UNSAccountB attributes using few of the employee attributes, for example:

person.personnelnumber -> or

person.centralaccount -> unsaccountb.<some attribute>

1. Where can I configure something like this? Is it a script, because I don't see this option in account definition? If so which one?

2. Is it possible to calculate attributes for unsaccountb attributes?

Kindly assist.