We recently enabled statecode and countrycode picklists in our address fields. These populate to quotes and orders (which are automatically created from quotes) and then a custom object called Shipments are created from orders in a button-launched Flow. How do I pass the values of the value of a shippingcountrycode or shippingstatecode to a state and country field in the custom Shipment object?

I have a flow where I tried to add the multiselect picklist values to a collection variable but this simply added all values as one value (e.g. "x;y;z" rather than "x";"y";"z". How do I add these as individual values to the collection so that I can use them in a loop?