This sounds like a perfect fit for Dispatch Messaging which is available in Unity Connection 7.0;
You can use the dispatch message feature to send a message to a distribution list (from either a call handler or interview handler). The message is configured such that only one user in the group needs to act on the message. When listening to a dispatch message, users are given the option to accept, postpone, or decline the message.
Dispatch messaging is useful in situations where a team is available to respond to issues, but only one member of the team needs to respond. For example, an IT department may want to set up a call handler to take messages from employees who need assistance, and then send the messages as dispatch messages to a distribution list comprised of IT department staff. All of the members of the distribution list receive a copy of each message. Team members can then decide whether to accept or decline a message; declined messages are then picked up by other team members.
In other Unity or UC Versions you would probably need to set up a "shared line" that appears on all the agent phones. This line would be the recipient for these group messages.
Hope this helps!