Other Mearas?

[Elianna]

This isn't related to resent posts, but still on topic:

Shadowfax went in the White Ship with Gandalf, of course. I saw that myself. I also saw Legolas let his horse run free back to Rohan from Isengard. Mr. Meriadoc says he does not know how many horses were lost; but there are more than ever in Rohan now, because no one steals them any longer...

Histories of M-E vol. 9. Sam's writing notes for the Red Book in this exert. The horses lost are the black horses stolen by the orcs mentioned by Firefoot.

Also pretaining to the original question: I don't think anyone's ever "possessed" a Mearas. Those noble horses only allow a few to ride them, I don't think that they're possessed....wait, "faithful servant, yet master's bane" servant, master, nevermind.