Use the Comments Channel for real time messaging
Once a Request is sent it will have a dedicated, private Comments external channel for each firm. This allows you to communicate with people in a firm who can access the Request. No firm can view another firm's channel.
There is also a Comments internal channel for communication with your colleagues on each Request. This is set up at the draft stage. Your colleagues who have shared access to a Request will see and can comment in both your internal Comments channel and your external Comments channels with each firm.