Free Lunch to....

...whoever can tell me where we saw the following adapted song from Chicago performed around 1980, at a Houston location that was NOT performing the musical:

We want Billy.
Where is Billy?
B-I- double L-Y....
We're all hiiiiiiiis.
He's our kind of guy,
And ooh what luck! 'Cause here he iiiiiiiiiiis!...

I did not realize until yesterday that this song was the same one! Duh! We saw it sung about 800 times one summer. Anyone remember? Come on- it's easy!