Hi @arunkumar,
you could use an expression language (e.g. JavaScript, JUEL, Groovy) to check if the list contains the value. This may look like:
validCountries.contains(selectedCountry).
As an alternative, you can use the FEEL extension and write a FEEL expression like:
list contains(validCountries, selectedCountry).
Does this help you?
Best regards,
Philipp