Port range forwarding

[Max Yin <max.yin@xxxxxxxxxxxxx>]

Hi,
I'm not sure if this question is already been asked before or not, 
because I can't find any discussion before.

I want to setup a port forwarding rule that will translate a specified 
port range to another port range, for example:

iptables -t nat -A PREROUTING -i eth0 -j DNAT -p tcp --dport 3100:3500 
--to-destination \
192.168.2.60:2100-2500

But I found that all connections from 3100 to 3500 will be mapped to 
2100 port only, not 3100 to 2100, 3101 to 2101, etc.

So, how can I make it? or is it possible ?

Thanks
Max