How to get scrolling text to appear only in the middle third of the screen?

[KG_BK]

Please see attached image.

How can you have scrolling text begin about a third of the way up the screen and end about a third of the way down the screen? I don't want the scroll to begin all the way at the bottom and finish all the way at the top. I only want the scrolling text to appear roughly in the middle, in a space that occupies the middle third of the screen, in between the two white lines in my screenshot. Thanks.  

[Peru Bob]

Create the text without a roll and then keyframe the position in the Motion Properties of the Effects Control Panel.

[Ann Bens]

Use a Mask from the Text in de Effect Controls.