As Danny says this is only a normal call with 5 people at one end.
I've set that up with 4 at one end, used a reasonable hypercardioid microphone, 4 people sitting at a semicircular table so they were in a 90 degree arc for the mic, looking at a 22 inch monitor. Two thick cloths on the table help to cut the sound reflection and make it sound a bit better.
The microphone gain (amplification) needs to be higher than usual, so the remote person is better using an earphone.
On Skype, for real conferencing (3+ locations and connections) you can only use audio without video. It works well with three, I do it regularly for family chats.