After well over a year since the release of Satisfaction Guaranteed, United Souls’ series of box sets collecting the Philadelphia International label’s complete studio albums is confirmed to resume with the April 7 release of Love Is the Message: The Sound of Philadelphia Vol. 3.  The third installment of the series promised to eventually encompass 15 volumes contains the following eight studio albums: The Ebonys, The Ebonys (Philadelphia International KZ 32419, 1973); MFSB, Love Is the Message (Philadelphia International KZ 32707, 1973); Bunny Sigler, That’s How Long I’ll Be Loving You (Philadelphia…