[server] KVM Guests each one with diferent Public IP

Hi everyone

im having this problem and im new at ubuntu
what i want to do is to have Virtual Machines (Virtual Machine Manager is what im using) on an Ubuntu Server with Gui (already have this) but
every VM should have its unique Public IP Address, i can use 5 in the same cable (eth0) for example the Ubuntu Svr (Host) has the ip 172.33.140.5 and i want the Virtual Machine (Guest) have 172.33.140.6 and so Guest2 .7 Guest3 .8 .

This is the network config i have

auto eth0
iface eth0 inet static
address 172.33.140.5
netmask 255.255.255.240
network 172.33.140.0
broadcast 172.33.140.15
gateway 172.33.140.1

auto br0
iface br0 inet static
address 172.33.140.5
netmask 255.255.255.240
network 172.33.140.0
broadcast 172.33.140.15
gateway 172.33.140.1
bridge_ports eth0
bridge stp off
bridge_fd 0
bridge_maxwait 0

i dunno what else can i do , if i need tu search for mac of the Guests and in a file assign them the IP
Any of your help would be so much appreciate