how to separate a flex data grid to display in different pages?

Firdt I should tell that I'm new to flex.

I have created a data grid using flex and xml. There, the grid have 20 rows and all 20 rows can be shown at once. But now I want to show 5 rows at a time. So I should have 4 pages of 5 rows, but with the same grid.
If anybody know how to do that please can you explain it?
And help is urgent!

Thanks in advance!