There seems to be a big push lately to decentralize the local church. The modern technology landscape opens the world to itself. There are a myriad of resources for leaders and open forums to discuss strategies and methods.
We have opened up our local church to online sermon notes, and even forgoing a local teaching pastor altogether. Some churches offer a streamed message from a speaker who nobody in the congregation will ever meet.
I believe the person leading the group should teach the group, whether that be a small Bible study, young adult ministry, youth ministry or even big church.