[Grammar] 'is' or 'are' proper singular group name

[FinLeavell]

Hello! My question involves the following two sentences. Can anybody help me decipher which is correct? My band's name is 'The Summer Obsession' and in our six years of existence I have never known the correct usage:

The Summer Obsession <b>are</b> a 3 piece rock band.

The Summer Obsession <b>is</b> a 3 piece rock band.

I've always used 'is' but have seen it used both ways in articles.

 

[tedtmc]

The Summer Obsession is a 3 piece rock band.

The Summer Obsession are a 3 piece rock band.

Both are correct.
'Is' refers to the group.
'Are' refers to the three band members.
3-piece should be hyphenated.

not a teacher