How to make a queue for one extension?

Question

Asterisk

Elastix 2.5.0
There are 4 employees who have their own unique functionality in the organization. Those. The questions that they decide - no one else will solve. Each has its own extension.
All incoming calls go to an IVR-voice greeting with a suggestion to dial the employee's internal number.
If the number of an employee who is already talking is dialed, there are short beeps and you have to call back.
How to implement the following functionality:
If the number is busy - play a notification file that the number is busy and a suggestion to wait for the employee's line to be released, start music_on_hold and, as soon as the line is free, transfer the waiting call to the employee.
?

Answer 1

Create 4 different queues with permanent agents and the desired greeting (this is your notification).
You do redirection on employment to the necessary queue from each employee.

Answer 2

If you don’t want to queue for each employee, follow me to his number, there is both an alert and music in anticipation.