We are able to condition one field at a time eith multiple dataset using the regex operator?
Don't understand what you mean. You want to condition against a multiselect fieldtype? For that you can use the REGEXP operator or the Contains operator. For REGEXP you'd use /VALUE_HERE/ (must be valid REGEXP). For Contains you'd just supply the value you want to match.
Is it possible to put 2 fields or more in the field area? For example [cb_field01]|[cb_field02]
Yes, you can substitute in whatever you like, but you should be able to just press the + button and add more conditions to your auto action as needed.