Yes! To see the availability of other LibraryH3lp users or queues, you'll want to buddy them (if you haven't already) - just as you would most any other IM account.
You can manually add a new buddy in the webclient for staffing. At the top left you will see "Guest & Contacts" with two icons after it. Click on the plus icon, this will prompt you to type in the LibraryH3lp username or Jabber ID for the new contact. The Jabber ID for a user will look like email@example.com and firstname.lastname@example.org for a queue. (If you are using a regional server instead of the main US server, you'll have to adjust the domain slightly to match your regional server. E.g. email@example.com and firstname.lastname@example.org for the Canada regional). Click 'OK' and your new contact will be added. If your new contact is logged into the webclient you will see their name appear in your contacts list. However, please note if your new contact is not logged into the webclient at the time you will not see their name appear but you will notice your total contact number will have increased by 1.
If you are using a third party IM client, it probably supports adding a buddy/contact.
But manual buddying gets tedious. To simplify the buddying process, your top-level admin user can opt to use the "Manage Contacts" capability within the users management page (US, CA, EU, SG). Details on how to use the Manage Contacts feature.