you can easily customize Nexus to do what you want. but it depends on what kind of response you're trying to do
i mean each filter has 1 thing in common,
you can ignore packets
do nothing
inject packets
disconnect user
if you're looking for this type of response it does exist in nexus and in navifilter too however you'll have to tweak the src code a bit.
i may help you with this, add me on skype
gold.fish530