Battery - Silver Trophy
Score 1,000,000 on the song Battery as a band (4 players)
This is how I got it with my band:
Guitar - Hard
Bass - Expert
Drums - Medium
Vocals - Beginner (Just to net star power)
we ended up getting about 1.2 million and we were about an average of 97% notes amongst the three of us. So this is absolutely doable. Find people to boost with to make this easier since the GH servers are pretty bare you won't easily come across anyone just through matchmaking.