Does anyone use pdfjam?

I have used pdfshuffler, imagemagik and pdfjam before to manipulate pdf files but I am having a hard time with this one.

I have three pdfs that have one graph on each page. The pdf are outputs of different model runs that I would like to compare side by side. So, each document has the same number of pages. I can easily combine them one after the other and within the same document compress pages onto the same page but not paste them side by side. The output will have the same number of pages of any of the components but probably landscaped. Visually, this is what I am looking for:

  pdf 1	      pdf 2	      pdf 3	         pdf pasted
| P1,1 |    | P1,2 |    | P1,3 |     |  P1,1 P1,2 P1,3 |
| P2,1 |    | P2,2 |    | P2,3 |     |  P2,1 P2,2 P2,3 |
| P3,1 | +  | P3,2 | +  | P3,3 | =   |  P3,1 P3,2 P3,3 |
| P4,1 |    | P4,2 |    | P4,3 |     |  P4,1 P4,2 P4,3 |
| P5,1 |    | P5,2 |    | P5,3 |     |  P5,1 P5,2 P5,3 |

Here is something close but still not right which I modified from a solution on stack overflow.

pdfjam d1.pdf d2.pdf d3.pdf --delta '-10 0' --nup 3x1 --landscape --outfile figureout.pdf

I know this is a very specialised question and I should probably ask it on stack overflow but just in case there is a pdfjam expert lurker on here. Thanks