; TIP547.LSP   Block Filtering   (c)1990, Timothy Robinson

(defun c:crowd (/ E1 ED CMD PT1 PT2
          SS1 SS2 LEN COUNT)
  (setq
    E1 (entsel "\nPick one block: ")
    ED (entget (car E1))
    N1 (cdr (assoc 2 ED))
    CMD (getstring "\nEnter command: ")
    PT1 (getpoint "\nPick 1st corner: ")
    PT2 (getcorner PT1 "\n2nd corner: ")
    SS1 (ssget "W" PT1 PT2)
    SS2 '()
    LEN (sslength SS1)
    COUNT 0
  )
  (while (< COUNT LEN)
    (setq
      E1 (ssname SS1 COUNT)
      ED (entget E1) COUNT (1+ COUNT)
    )
    (if (not (equal N1 (cdr
        (assoc 2 ED))))
      (setq SS2 (append (list E1) SS2))
    )
  )
  (setq LEN (length SS2) COUNT 0)
  (while (< COUNT len)
    (setq
      E1 (car SS2) SS2 (cdr SS2)
      COUNT (1+ COUNT)
      SS1 (ssdel E1 SS1)
    )
  )
  (command CMD SS1)
)