Javascript of merge to place a page from a source document in every other page of the existing file

Hello - 

I am looking for a script that will allow me to merge two pdf files and place them in such a way that a source document page is placed in every other page of the exisiting document. For example, if you have an odd sequenced page number and even sequenced page number, and you'd combine them to form a 1, 2, 3... sequence. 

Any help is appreciated!