Model Batchplot

[3arizona]

can someone help me modify a lisp i found on this forum? Can this lisp be modified to combine multiple files into one PDF. Also, can this be set to a path on my "C" Dive? 

(vl-load-com)
(defun c:exPDF ( / ss ed obj i box ll ur pt1 pt2 pdffile tag val)

   (setq ss (ssget "X" (list '(0 . "INSERT")'(2 . "test1"))))
   (if ss
      (progn
         (setq i 0)
         (while (< i (sslength ss))
            (setq ent (ssname ss i)
                  obj (vlax-ename->vla-object ent)
                  box (vlax-invoke-method obj 'getboundingbox 'pt1 'pt2)
                  ll  (vlax-safearray->list pt1)
                  ur  (vlax-safearray->list pt2)
            )
            (while
               (and
                  (setq ent (entnext ent))
                  (= "ATTRIB" (cdr (assoc 0 (setq edata (entget ent)))))
               )
               (setq tag (cdr (assoc 2 edata)))
               (setq val (cdr (assoc 1 edata)))
               (cond
                  ((= tag "JOB#")   (setq job val))
                  ((= tag "PART#")  (setq part val))
                  ((= tag "RELEASE")(setq rel val))
               )
            )
            (setq pdffile
               (strcat
                  (getvar "dwgprefix")
                  job "-" part "-" rel ".pdf"
               )
            )
            (command "-export" "_P" "_W" ll ur "_N" pdffile)
            (setq i (1+ i))
         )
      )
   )
   (princ)
)

Thanks.