Yes - there’s generally three options: 1. Just take the ARN or id of the external resource and pass it directly. 2. Use .get static methods on reaources to populate a full resource object based on an id, in case other properties of the object are needed. 3. Use the .getXYZ functions on modules like

aws.ec2

to find information about resources via more free form calls to the underlying provider. For example https://pulumi.io/reference/pkg/nodejs/@pulumi/aws/ec2/#getSecurityGroups