Approval with with filtered list of dynamic names

Hi,

I'm looking for a way to select multiple dynamic approvers from a list based on values in column. The difficult part is that the column may have multiple values in a comma separated list. In which case I'd like it to select all the relevant users for approval.

In this case the column is countries and the user can select one or all the countries effected, each country has a specific approver. If it's just one country picking the used of a list is fine. I can't find a way to select multiple approvers if the field contains several countries. I was looking at the query list, but the contains filter won't work for multiple countries. 

Am I missing something obvious? 

Thanks!