yes, but it's almost quicker to do it in goldwave. In reaper, you would need to freeze the track, which would render it in place so you'd have an audio track not a MIDI one. Then, you'd shift F2 Alt H then enter to clear the preserve pitch when changing tempo checkbox. Then place a stretch marker near the end with CTRL + SHIFT + M then control M to edit it. Uncheck the box that says link start and end, then set the end to 0.001 and enter.
I made an organ using multiple instance of Oatmeal. Load up this reaper project and it'll put a bunch of oatmeal instance on a track. This shows how you can chain them together. Because it's oatmeal, it's a bit ghetto in that you have to shut off oscillator 1's amp on the 2nd through last in the chain because you can't control where it starts like you can in Sylenth. This patch would have been easier and less time consuming to make in Sylenth.