In URu2Si2, heavy fermion superconductivity emerges out of an unusual "hidden order" (HO) phase. This contradicts the paradigm that unconventional superconductivity occurs in "domes" around quantum critical points (rather than within another ordered state). In spite of decades of intense research, the character of the HO state remains controversial. We have synthesized a new series URu2(Si,P)2 in which we electron-dope the ligand sites. In contrast to other "tuning studies", this path yields very high quality single crystals and does not require a pressure cell. We find a complex phase diagram, including the consecutive suppression of superconductivity and hidden order, followed by the evolution of a new antiferromagnetic phase. We propose to use single crystal magnetic neutron diffraction to shed light on the magnetic ground states of two key specimen in this doping series.