I have one analog line and 3 extension from provider with same number

[Bilalikram]

I have one analog line and 3 extension from provider with same number, I want to configure it with 3CX telephone system.

can you please guide me which analog device is better for this solution.

Also what do i need to do if provider gives 3 extensions under same number? do i need to configure only 1 line or 3 of them for 3cx

please advise what will be suitable solution for this

Thank you