By default, all numbers assigned to a Site show in the caller ID dropdown and all numbers assigned to a Call Queue show up for all members of that queue.
We have Sites and Call Queues with many numbers assigned to them (over 100 numbers) and there's no easy way to hide all those extra numbers.
We currently have to assign the numbers to a different "Number Inventory" Site and use custom rules to route the calls to the proper call queues. This hides the number from the dropdown but is quite cumbersome to manage and affects reporting and call log access for those numbers.
The ability to toggle show/hide number in caller ID dropdown would be very useful.