Yes i think it is.
The devotionals will still show up on your main feed, or your main story list, but your devotionals will be the only thing on the publication you create for that.
I also have a publication with a friend that dogs write. its a lot of fun, . everything is from the dog's point of view. Do you have a dog who might have something to say? :).
The other option is to create a secondary medium account, which might work but a lot of extra expense.
SO yea create a publication for your devotionals. YOu will submit them to your own publication like you do to any publication, and then you have to publish it.
I wonder, what if a few christian writers got together and created a devotional publication?