This template enables the Security Hub finding aggregator for all regions except the ones specified.

Terraform Template

resource "aws_securityhub_account" "example" {
}

resource "aws_securityhub_finding_aggregator" "example" {
  depends_on = ["aws_securityhub_account.example"]
  linking_mode = "ALL_REGIONS_EXCEPT_SPECIFIED"
  specified_regions = ["eu-west-1", "eu-west-2"]
}