You can set a rhythm set to midi channel 10. So you'd have part one be the piano and then skip all the way over and set a drum kit for part ten.... now as for having a drum beat playing while you play the piano, you'd have to either program this in on a computer or if you can on the keyboard and then play it via midi.... or just play the drumbeat manually while you play the piano. This would be very difficult though. You may want to look into getting a cheap drum machine so you can program drum parts in.

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John 3:16 For God so loved the world, that He gave His only Son, that whoever believes in Him should not perish, but have everlasting life.