How to add More Ip on a GRE TUNNEL

[yena]

Hi i have created a GRE tunnel for anti Dos remote protection service in this way:

Gre remote address: 777.59.162.36
Gre tunnel local address: 777.59.166.145
Gre tunnel remote address: 777.59.166.144/24

I have added OPT2 interface and the static route:
TunnelGRE OPT2 777.59.166.144 777.59.166.144

All works.
Now i have to add more "protected ip"
777.59.166.173
777.59.166.227
777.59.166.228
…
But i can't add this as virtual ip because OPT2 haven't a static ip.
How can i add the new ips?

Thanks!