Not yet.
Our solution was using doodle.
But we created an Intranet with wordpress for our partners. We sent a mail with the url post with the specifications of the activity. Then you can use an embed page in the post with the doodle information. It’s not the same, but probably works.
Another way it’s make the same embed page using google forms. It’s not as potent as doodle. We use embed google forms for other uses.
I don’t remember the embed application but there aren’t so much. If you need the name of the embed application please ask here again and I will find it.
Carles