Create a new IAM user in the company's AWS account for each of the third-party authenticated users from the supplier organizations. The users can then use the IAM user credentials to access DynamoDB

Use Cognito User pools to enable trusted third-party authenticated users to access DynamoDB

Create a new IAM group in the company's AWS account for each of the third-party authenticated users from the supplier organizations. The users can then use the IAM group credentials to access DynamoDB

Use Cognito Identity pools to enable trusted third-party authenticated users to access DynamoDB