Triggering Groove Agent One with electronic drums

I am trying to use a Yamaha DTXPLORER electronic drum kit to trigger Groove Agent One within cubase 6. I also have a Yamaha KX 25 MIDI keyboard. Can I use that as an interface between cubase and the drum kit? If not, what is the best way? The drum kit “brain” has a MIDI out. The KX 25 MIDI keyboard has both a MIDI in and MIDI out. I’d really appreciate any help anyone can give.

Drum brain MIDI out to interface MIDI in.

Indeed! And also check following settings in your KX:
MIDI Select: USB
Consult pages 37-38 in your Owner’s Manual.