I guess you can use the <quote> tags to hide part of the text. You must wrap the text with <quote> and </quote>.
For example:
Line 1
Line 2
Line 3
Line 4
Line 5
Line 6
Line 7
Line 8
Line 9
Line 10
Line 11
Line 12
Line 13
Line 14
Line 15
Line 16
As you can see, the first 10 lines are displayed, but the rest is hidden by default.