For example, you need to assign the IP range 192.168.10.6 – 192.168.10.100 to your eth0 interface.
Create a range file in /etc/sysconfig/network-scripts/ifcfg-eth0-range0 as below
DEVICE=eth0 BOOTPROTO=static IPADDR_START=192.168.10.6 IPADDR_END=192.168.10.100 NETMASK=255.255.255.0 CLONENUM_START=1 ONBOOT=yes TYPE=Ethernet
CLONENUM_START is the number that will be assigned to the first IP alias interface (eth0:1 in this example).
If you need to add more ranges of IPs then just use a different file for eg. ifcfg-eth0-range1, for each one of the ranges. Make sure CLONENUM_START does not overwrite other aliases.
Once you have configured the range/s of IPs you just need to restart the network service in order to activate it