Yes you can, however, the thread will not be eligible for the collection of Life Points unless a character that is played by another player joins in.

Your characters are also allowed to mention one another in each other's posts as long as there aren't any huge interactions between the two. If the thread revolves around the two characters socializing with one another, separate posts (for each of the wolves' actions and reactions) are recommended as opposed to having one large post from only one character.