Question about printing Poster setting in Adobe Acrobat Pro

I'm wondering if this is possible. I have a PDF file that is aproximately 20"x 20" and my printer's maximum width is 17" so I'll have to print it out in the poster setting in the printer dialog box. I'm going to use a paper size of 17"x 24" so that it will print in two sections and I'll have to piece it together. As far as I can tell it will devide the image equally between the two pages. My question is there any way to move it across the two images so that most of the image in one the first paper? I've attachwd tow screen shots trying to show what I want to do. The second image shows how I would like to print the two sections out with all of the image on the first page and the key to the right on the second page. Is this possible? If it is how would I set it up?

Thank you,

Linda