Could you please specify which module you are using for importing CSV and what you want to do with the CSV? Do you need to map the CSV data to Mendix objects or soley save it as a file so that you can "send the file"? If you only need the latter, then there is no need to worry about the separators in the first place as you can just upload the file, e.g. by using the File Manager widget.
Also, could you please elaborate where the need to have multiple separators is coming from? For you data, would it be feasible to replace all instances of one separator, e.g. the ";" in your example with your primary separator "," before doing the actual CSV import?