Yes. You can add as many contacts to a case as necessary. To do so follow the below steps:
1) From the Case Detail page of a case, click "Edit Case".
2) Click the "+" sign next to the primary client tab, then select the type of client.
Note: If the client type you would like to add is not available in the drop-down list, then you will need to add it by going to "Settings" and then "Client Types" under Case Customization.
