It would be very helpful to have the option to set concurrency limits on a per-phone-number basis. For example, if a number is limited to five concurrent calls and a sixth caller comes through, that caller would be placed in a queue with hold music until a slot becomes free.
It would be ideal if we could also configure what the caller hears while queued. Either a custom spoken message we provide or a recorded audio file that we upload would work well. This would allow us to give callers clear expectations rather than letting the call simply fail or overflow.
This feature aligns with the way concurrency is billed. Once you go beyond the included amount, it costs per additional concurrent call so being able to set specific limits per client would allow us to offer tiered pricing that matches the concurrency they choose. At the moment we need to build a fairly complex PBX-style setup to enforce these limits which adds operational overhead and is not as clean as having Retell handle it directly.
Adding this functionality would make concurrency management far simpler, fairer for clients, and more consistent with how the platform is already priced.