merge ms word files and create Table of Content

Hi,

I have two word files with headings i am attaching my samples and an output file below. i want to merge two files and create a table of content to that merged file.

 

1 word doc has 3pages and 2 word doc has 3 pages in the merged word doc we should get 6pages and create a table of content to that merged file headings. you can suggest any third party dlls also.