Hi,

Is you List collector variable referring to a OOB or custom table?

My simple solution would be like:

1. Create a new String field in your referenced table called group emails.(or use existing if you have any unused field).

2. In the new field give all the emails with comma separated .

For Example: For A option input your 1,2,3 email address

Similarly do for all the options

3.Write a script in workflow to trigger the event  -

GlideRecord its table and get the values you created for the corresponding options ,Push in a array and get unique values

Parse that value to event.parm1-so you ill get the recipients list for notifications

Please mark my answer helpful/correct if it resolved your query

Thanks