crowded page

[胡海鹏 - Hu Haipeng]

Hello,
  I'm writing my second orchestral work. There's a place two systems having different height, one low and wthe other high with more instruments. Lilypond always tries to include all two on one page, and therefore generates "couldn't fit music on page". I have to use manual break, but can Lilypond not do this stupid thing itself? This is the place I can find, and when making parts, I can't find anything because only one or two staves are used.
  How can I provide a small snippet? Using easy notes doesn't generate such issue.

Regards
Haipeng