What you could have is a script with uses basename to get the name which was used to call it. Example: fn=$(basename $0)
You then make two links in the same directories as the S10network link.
Example: cd /etc/rc.d/rc3.d/ ls -s /etc/rc.d/init.d/my_iptable_rules S10before_net ls -s /etc/rc.d/init.d/my_iptable_rules S10network_up
Now a ls S* we see something like S10before_net S10network S10network_up which indicates the order they will execute when the system boots.
Now my_iptable_rules could have a test like
if [ $fn = S10before_net ] ; then (load iptable with a restriced set of rules here) fi
if [ $fn = S10network_up ] ; then (load iptable with some more rules here) fi