Can a Client Connect to Multiple Virtual Hosts of a RabbitMQ Instance?

Yes.

Virtual hosting is a basic feature of RabbitMQ. Each virtual host (vhost) serves as an independent RabbitMQ server. Different vhosts have different data directories but share the same process. Connecting to multiple vhosts does not differ much in performance from connecting to one vhost. The only difference is that the RabbitMQ process has more objects. You are advised to test the performance by using the service model.

For details, see Virtual Hosts on the official RabbitMQ website.