Script to send notification to different email addresses based on variable response

I have a RITM with a list collector variable with three options, we'll go with A, B, and C for simplicity.

The ask is that a notification is sent that includes all stakeholders so they can reply all and keep a chain of questions/comments together. I built a custom workflow already as they asked for this notification after the first task is closed and fire at the same time as the second (attached pic)

The problem is each option has a slight variance of email addresses.  If A is selected a notification needs to a group of email addresses, lets go with groups 1, 2, and 3.  If B, 1, 2, and 4.  If A and B 1, 2, 3, and 4. If c, 2, 3, 5, 6 and if all selected then email to 1-6.

I am struggling on how to make this work, a script in workflow somehow, a business rule, someone figure a way to pass the string from workflow to a decision table?

All of the above I am not great at yet or know much about as I'm a youngling in my Admin/DEV career.  Any suggestions would be appreciated!