Would it be possible to indirectly kill people? When John Zeärtö would write: Johnny Riler Accident. Tomorrow Johnny Riler will receive a piece from the death note. He writes the true name from the person who uses the alias Xavier. Would that work? (And yes Johnny knows the true name)
This scenario is totally possible. As long the 2 main factors can be reached. 


This note will not take effect unless the writer has the person's face in their mind when writing his/her name. Therefore, people sharing the same name will not be affected.
The conditions for death will not be realized unless it is physically possible for that human or it is reasonably assumed to be carried out by that human. 


So if he knows the real name, and can bring the face of the person to mind. And it is physically possible for that person to obtain a piece of death note and write in it. Then yes it is possible indeed.