Excel Multiple conditions IF OR AND

I need to create an Excel one formula that will pick up the following conditions:

1. 1. If have only Sweden =IF(C12:C27="Sweden";"SE05")

   2. If Sweden and Norway, then the code is CH51 =IF(OR(C12:C27="Norway";C12:C27="Finland");"CH51"

   3. Multiple courtiers, any of countries like Sweden, Norway, Finland =IF(C12:C27="Sweden";C12:C27="Norway"; C12:C27="Finland");"GB80";"")

When I used the formulas separated they work, however I need to combine them together, so it make sense. I tried to use OR /AND together with IF formulas, but it did not return the correct values. I use this =IF(AND(C12:C27="Norway";C12:C27="Finland");"CH51") but then it returns CH51, even if I have all the countries in the list (Sweden, Norway, Denmark)

Can you please advice what formula to use to return all the conditions in the right way?

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