I've seen this done before by posting a video to a Facebook page, hiding the video from the page, and then sharing the video post to the Facebook group(s), and finally creating an audience out of people who watch the video from more than X% so that you have a really engaged audience to retarget and introduce yourself to.

If you do this tactfully, and in the right groups, you can very quickly build targeted audiences that would have been extremely difficult, and likely expensive, for you to get otherwise.

Here is an example of how you could combine this tactic with Octane AI. For this example, let's imagine that you are a nutritional related brand:

Create a video for your Facebook page that talks about some interesting nutritional facts related to your product, but not directly selling your product.