There are a few ways you can block those already registered. You can use a filter based on member status, but I use the filter "Not Filled Out Form", just in case something goes wrong with program status updates. Under the "Smart List" tab, add the filter "Not Filled Out Form", chose from name "is" (form) and put the date of activity. For instance, our first invite goes out the first week of the month, so I use "in the time frame" "This Month". Hope this helps!
Thank you. I had tried that before and my results came back as 0 but I tried it again it worked this time! Thank you.