Message filter syntax help required

[Vinay babu]

Does the below syntax correct, can you confirm. The email address should be case-insensitive and separated with OR condition. Thanks.

External: if (header("from") == "(?i)(morning.alerts@exmaple.com\\.com|anirudh.ken@example\\.com|survey.ECIL@exmaple.com")) {

                         insert-header("X-custom header", "");

                     }