We found that during the initial discovery phase of your project, having an open-communication format where a client can openly communicate with our interested experts at the same time helps to speed up the process of clearly defining your project, resulting in a more thorough scope of what you'd like delivered and preventing you from having to answer the same question more than once.
If you'd like to reply to a specific expert, you can just address that person by name and answer their question.
Your project won't be private until you've hired one of our experts, but don't feel obligated to contact all experts if you have a good dialogue with one or a couple already.
If you feel more comfortable privately speaking/working with a specific expert, you may create a new project with that person listed as your 'Preferred Expert'. At that point, the new project will be private for just the two of you to discuss the details of what you'd like done.
(Or if you'd like us to help you with this, we'll happily duplicate your project for you and your chosen Preferred Expert.)