Confirmed. You can post from a microblogging platform (e.g., #Mastodon, #Akkoma, etc.) to #Piefed simply by mentioning the group actor in your post.

Piefed sticks a [Microblog] descriptor in the title so that #Lemmy, #Mbin, and Piefed readers know that the post originated from a microblog.

To use this feature, you need to use @ for the mention instead of !. For example @community@exampleserver.com.

This is yet another reason I’ll be using Piefed to create communities.