[IPTABLES] Is it possible to add multiple sources (IPs) in a variable?

Also, i need to know if this would work with MAC addresses, I hope so, less lines = better ;]

IPtables allows single IP's or a netblock (on standard subnet boundaries) to be specified. For discontiguous ranges or a range that isn't wholly contain in a standard subnet you must specify each IP individually.

Since MAC's are by their nature unique each will require a separate rule.

I have seen some places that use kind of like a loop and a txt file i think, i would like to do this, im just not very familiar with the syntax's, let me paste an example i have found:

#!/bin/bash

if [ -f badips.txt ]
then
        for BAD_IP in `cat badips.txt`
        do
                iptables -A INPUT -s $BAD_IP -j DROP
        done
else
        echo "Can't read badips.txt"
fi

I'm not sure if something like this would suit me or not.. would the above go into my firewall txt file?  

thank you, but i figured it out on my own, works wonderful, thanks ;]