Simplex Conference Style system

Hi All,
I have an unusual request for a system as follows. A church group want to make their programme available to members that are unable to attend due to sickness etc.
They want to connect to a server via POTS to uplink live content and then the users dial in as required, giving a conference number to connect to.
The problem I have is how to make it simplex, ie. the users should not be able to hear each other, only the uplink.
My thoughts so far include:

  1. Getting a DID from a VOIP provider.
  2. Setting up an asterisk server on a VPS hosting service.

Any thoughts and suggestions would be appreciated.
In essece I need a streaming solution to multiple POTS users. A full internet solution will not work as some users are elderly and infirm.