hi all, question again..

i have a large collection of *.tar.gz's in
/opt/ftp/pub/NetBSD/packages/distfiles

i edit /usr/pkgsrc/mk/bsd.pkg.mk this way:

--- bsd.pkg.mk  Thu Aug 10 05:20:07 2000
+++ bsd.pkg.mk.new      Thu Aug 10 05:19:51 2000
@@ -555,6 +555,8 @@
 
 # The primary backup site.
 MASTER_SITE_BACKUP?=   \
+       ftp://localhost/pub/NetBSD/packages/distfiles/${DIST_SUBDIR}/ \
+       ftp://localhost/pub/NetBSD/packages/distfiles/NOUD_PORTS/ \
        ftp://ftp.netbsd.org/pub/NetBSD/packages/distfiles/${DIST_SUBDIR}/ \
        ftp://ftp.freebsd.org/pub/FreeBSD/distfiles/${DIST_SUBDIR}/
 
dev# 

deattach the network cable and build a few /usr/pkgsrc/meta-pkgs,
using some pkg-tar.gz's i mirror in my /opt/ftp.

how do i get the same effect w/o deattaching the networkcable,
nor edit my routing table, my name server or use squid/squirm ??
is there some defined thingy in /usr/pkgsrc/mk?

(i'm not regular on these lists, an e-mail responce to me as well would be
nice)
thanx,
~n