The group was The Young Bloods.....The song title is ’Get Together’

Jessie Colin Young and the Young Bloods were one of classic rock’s true, "one-hit-wonders".

This Dino Valenti song had previously been recorded by the Jefferson Airplane, but The Youngbloods’ slow, soulful interpretation of "Get Together" was definitive. The record faded quickly but suddenly rocketed to the Top 10 when it was re-released in 1969, after it had been used in a television public service ad. This song adopted as a counter-culture anthem for the Vietnam War demonstrations.

On a personal note. One great memory that I have was when I was 17, being at Woodstock and singing "Get Together" as we walked down the road towards that first show on Friday. 

Almost everyone had abandoned their cars the night before and the road was filled with people walking both directions. Far ahead I could hear a sound, then it turned into a song, and as I walked it got louder and louder until I could tell it was “Get Together”. As it got louder the people all around started singing and smiling as we moved slowly along toward it. Finally I could see that it was a guy who playing his guitar in a rocking chair on top of a truck that was going the other direction, very slowly. As we passed, everyone was singing and feeling it and for that moment we did understand, and it was as true as anything can be. As we continued on, the song slowly receded, and the people around left off singing, but I could hear the song as it kept going down the road behind us.

WOW! What a flashback!

Love is but the song we sing,
And fear's the way we die
You can make the mountains ring
Or make the angels cry
Know the dove is on the wing
And you need not know why
C'mon people now,
Smile on your brother
Ev'rybody get together
Try and love one another right now
Some will come and some will go
We shall surely pass
When the one that left us here
Returns for us at last
We are but a moments sunlight
Fading in the grass
C'mon people now,
Smile on your brother
Ev'rybody get together
Try and love one another right now
If you hear the song I sing,
You must understand
You hold the key to love and fear
All in your trembling hand
Just one key unlocks them both
It's there at your command
C'mon people now,
Smile on your brother
Ev'rybody get together
Try and love one another right now
Right now
Right now!

I had forgotten this song - thanks for a good memory!

EVERYBODY GET TOGETHER
 (Chester Powers)

 Love is but a song to sing
 Feels the way we'll die
 You can make the mountains ring
 Or make the angels cry
 Though the bird is on the wing
 And you may know not why

 Oh! Come on you people now
 Smile on your brother
 Everybody get together
 Try to love one another right now
 Come on you people now
 Smile on your brother
 Everybody get together
 Try to love one another right now

 Some may come and some may go
 He will surely pass
 When the one that let us heal
 Returns for us at last
 We are but in the morning sunlight
 Fading in the grass

 Oh! Come on you people now
 Smile on your brother
 Everybody get together
 Try to love one another right now
 Yes! Come on you people now
 Smile on your brother
 Everybody get together
 Try to love one another right now

 Come on you people now
 Smile on your brother
 Everybody get together
 Try to love one another right now
 (repeat and fade)

http://www.mathematik.uni-ulm.de/paul/lyrics/dc5/everyb~1.html