I can suggest one thing to do.
You can change the broker name to its Fully Qualified Domain Name( FQDN).
Ex: if it is now "broker_name" you can change it to "broker_name.xyz.com" and then ask everyone to connect to broker using FQDN from both workbench and administrator.
How to change broker name to FQDN ,you can refer Page 346 of Implementation Guide of R12.5 Bookshelf.
I am mentioning it here anyways but do consult the bookshelf.
Windows
In Control Panel, System, Environment Variables, add, as a SYSTEM VARIABLE, the
variable RT_FORCE_NODE_NAME with a value of m1.company.com
UNIX
Add RT_FORCE_NODE_NAME=m1.company.com; export RT_FORCE_NODE_NAME to
the USER PROFILE for every product user on the computer or the SYSTEM PROFILE.