The Melchizadek Priesthood was the predecessor to the Great High Priest of the Tabernacle. There was only one at a time, and death ended the position of High Priest (it could be ended other ways, but there was always only one at a time).
The Bible is very clear that Jesus is our Great High Priest, in the order of Melchizadek, a Priest forever now because He is risen and thus alive forever more. There can only be one at a time and Jesus is the only One now, so the mormonism faux melchizadek priesthood is not only fake, it is a great blasphemy toward the Jesus of the Bible. But then, the jesus of Mormonism isn't the same Jesus of the Bible anyway, so I suppose Mormon men claiming the melchizadek preisthood can excuse themselves for their blasphemy. I don't think God will excuse them, though ... are you reading along, Sandy? The Mormonism melchizadek priesthood is a blasphemy, one of many in Mormonism, Sandy.