Our team is running MQ v9.2 and need to test multiple clients on the same QMGR. We are using UserId for authentication and not sure how to handle authentication and ACL. Is there a way to handle authentication on the channel level?

There are many ways for configuring mq channel authentication. It all depends on the environment and requirements. You will need to set up the channel authentication rules and test to see if the requirement you are trying to achieve is met. For your testing alongside the channel authentication rules you may need to grant mq authorizations against mq objects that the Userid from the Connection will be using. That will be via MQ Explorer or setmqaut ... an example of the Authorizations may be Connect to QMgr, Put and Get from specific Queues .. etc.

See the following documentation for more information:

1) Channel authentication records

https://www.ibm.com/docs/en/ibm-mq/9.2?topic=mechanisms-channel-authentication-records

2) CHLAUTH Made Simple: Common Scenarios and Examples and How to Verify them with RUNCHECK (rev4)

https://www.ibm.com/support/pages/chlauth-made-simple-common-scenarios-and-examples-and-how-verify-them-runcheck-rev4

3) Working with MQ Channel Authentication Records

https://blogs.perficient.com/2019/07/26/working-with-mq-channel-authentication-records/

4)

Once a User / App has been allowed an MQ Connection to the Qmgr a Customer may want to only grant them particular Authorizations on an MQ Object/s that is where MQ runmqsc setmqaut command comes in (or can be done via MQ Explorer).

setmqaut (grant or revoke authority)

https://www.ibm.com/docs/en/ibm-mq/9.2?topic=reference-setmqaut-grant-revoke-authority