Can't save multiple Excel sheets to one pdf using Applescript

I have an Excel workbook with 6 worksheets. I want to save four of these worksheets as a single pdf document.

If I was doing this manually, I would set the print area for each worksheet. Then I would select the first worksheet and then select the other worksheets such that all four worksheets were selected. Then print the workbook to pdf.

I would like to automate this simple process in Applescript. I have set up Applescript to set the print area for each sheet. I can’t seem to find the correct AppleScript to select the four worksheets and save them as one pdf document.

Can anyone help?

Thanks in advance.

Model: Macbook pro
AppleScript: AppleScript 2.2.4
Browser: Safari 536.30.1
Operating System: Mac OS X (10.8)