Great question @MattG876!
Since we would need you to have a Facebook Page in order to use the Simple Share posting feature, the best workaround to post to your group would be to grab the short URL of your email campaign!
Once your campaign is sent, you will see a link icon next to the name of your campaign:
This will give you a webpage version that you can post to your group in order for them to view your emails.
Let us know if you have any additional questions!