Create a different Amazon Simple Notification Service (Amazon SNS) topic for each partner. Configure the Lambda function to publish messages for each partner to the partner's SNS topic.

Create a different Lambda function for each partner. Configure the Lambda function to notify each partner's service endpoint directly.

Create an Amazon Simple Notification Service (Amazon SNS) topic. Configure the Lambda function to publish messages with specific attributes to the SNS topic. Subscribe each partner to the SNS topic. Apply the appropriate filter policy to the topic subscriptions.

Create one Amazon Simple Notification Service (Amazon SNS) topic. Subscribe all partners to the SNS topic.