No, G70 doesn't have that........ nice idea, wonder why they dropped it?
There are solo and mute buttons for the parts, and ways to go to B&D only and back, but nothing like that (although you could program a UPG with the setting and bang into it on the fly......)
It seems Roland always look for the MOST useful feature in an arranger to leave off the next model...... (hint, hint, Chord Sequencer......!)
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An arranger is just a tool. What matters is what you build with it..!