You can interact with Lemmy posts from Mastodon but I'm not sure about Mastodon from Lemmy. if you enter your name @DonDino@mujico.org in your Mastodon search bar you will have federated your Lemmy and Mastodon instances and you will be able to view a copy of your Lemmy posts and discussions on Mastodon and other Masto users who are federated with you can see these and boost or reply as well. It's also helpful to enter the handle of the Lemmy community you'd like to view in the Mastodon search bar ( asklemmy@lemmy.ml for this community specifically ) and you can follow Lemmy discussion for specific communities there and boost them to share to your Mastodon followers.

Sorry if I misunderstood. Unfortunately I don't believe the opposite is possible so you won't be able to see Mastodon posts in your Lemmy feed the way you can see Kbin posts. Maybe someone else has a more useful answer.

In the web interface, search "all" with the link. Worked for me