What is best for Receptionist - shared line; call queue; delegation; other?

Our receptionst will be out for an extended period and so we need our main phone number, which obviously goes to her extension, to ring to 4 other users so whoever is available to answer, can. We have several IVR menus set up so whatever we do it needs to start on her extension. I hope this makes sense! I’m not familiar with the difference between a queue or shared line or delegations to know what’s best to fit our situation.