Okay, I’ll try that letter scramble with another clue or two. This group had five top 40 hits in the mid- to late ‘70s. And…reading from Wikipedia now, this song peaked at No. 3 in 1978, not 5 as I stated earlier. They were known as a progressive rock group and they have a one word name that begins with one of these letters: (song title, band name, song name all scrambled)

MHFIADP

The songwriter, group member, and singer’s initials are not scrambled.