Is it possible to use different styles in the same score?
I want to use the orchestral style for the vocal staves and only an accolade (with upper grand staff and lower grand staff) for the organ accompaniment, but now the tick line from the orchestral style is drawn all the way down to the last staff, instead of having only a thin line.
Is there a solution for this?
Are you asking about the thick and thin vertical lines at the left of each set of staffs? If so, I think you're stuck with them - I don't think there's any way to fiddle with that within NWC2. You might print to a metafile and alter that with a graphics tool, before printing to paper, but that's a bit beyond me.
The actual bar lines won't extend from the orchestral to the upper grand staff, so that will give you some visual separation. To make it more pronounced, you could adjust the vertical sizes of the staffs.
It can't be done yet in NWC.
When it has been important I'e done it by adding the orchestral bracket thingies afterwards by pasting them as graphical elements in the layout program.
To get them, set up the choral staves as orchestral so the bracket appears, then use the copy file to extract. Alternatively, which is what I do, is to print the page from NWC to a postscript file and use Ghostscript to extract a high res. bitmap file which can be used in many graphical editors.