Yes! You can send an unreleased tracks and demos on Groover.
Uploading an unreleased track or demo
You have 2 main options (you only need to do 1 of them!):
Upload your track to YouTube using an unlisted, embeddable link (Not sure how? see details here)
Upload your track via a private Soundcloud Link (more details here)
TIP: If you know your release date, don't forget to indicate it! That way, if you're looking for shares & visibility, the curator will be warned not to share your track until it's released.
Tips on sending demos
Feel free to submit demos to get feedback from curators. Check out this article to learn how to get the most out of your campaign when sending a demo.