this is definitely a group of guys from the 60's/70's. There are so many for me, some already listed above. Here's a few more that aren't yet.
Chicago - "25 or 624" (actually the whole CTA album)
Eric Clapton - "Layla"
The Doors - "Riders on the Storm"
Boz Scaggs - "Loan Me a Dime"
Genesis - "Musical Box", "Lamb Lies down . . .", "Supper's Ready"
Elton John - "Madman Across the Water"
definitely not all of them . . .