Hi,
In the Key- or Drum Editor, you can Shift + double-click to any Note. This note you click on will be selected + all following notes of the same pitch. So if you Shift + double-click to the first note, you select all notes of the pitch. Then Copy, select the other (new) track and the Paste at Origin (if you don’t want to take care about the exact position manually).
Moreover in the Key Editor, you can Shift + click to the virtual keyboard on the left side, to select all notes of the pitch. Then again Copy, and the Paste at Origin.