ALV with multiple headers

Hello All,

i have a requirement where i have to have multiple headers in a single alv.

The exact requirement is like.

Header1----

row1

row2 1 unit

row3

row4----

Header2

row1

row2

row3

row4

Header3

row1

row2

row3

row4

and the number of individual units is not fixed and will be determined at runtime.

Can somebody tell me the steps to achieve it.

actually i tried using block alv in loop but it is showing inconsistent data and moreover it has a limitation of 19 appends.