PDF Merge - merged report pages are not continuous but starting in new page.

we tried using - FOUtility.mergeFOs(java.io.Reader[] foReaders, java.util.Properties prop) to merge and create a single PDF file but its not working as expected.

Issue:
The space of output pdf page 1 is discarded and the second merged file always starting in new page.

Input:
Report1 having 1 page
Report2 having 2 pages - (another description )

Expected Output PDF:
Page 1 ( report1) , Page 1( report 2's page1 and continues ) to page 2(report 2)

Actual Output PDF :
Page 1 ( report 1), Page 2( report 2's page1), Page 3 ( report 2's page 2)

Issue:
The space of output pdf page 1 is discarded and the second merged file always starting in new page.