piano composition with 3 staves

In a piano composition I need in some bars 3 staves. Is this possible? I cannot find anything about it in the manual and in forum.

Try this thread from earlier today:

https://www.steinberg.net/forums/viewtopic.php?f=246&t=111682

Thank you, but unfortunately I have already a first flow and I need the bars with 3 staves in the second flow. It seems that it is not possible to import a musicXML in a second flow?

Not yet, but it will be in a future update.