Utilizing two DVR's using four cameras on one Router---Possible??

Hello, I have a Q-See Video Survelliance System using four (4) Cameras.
I want to purchase another Video Survelliance system of a four (4) Camera system.
Can I configure the two systems to work thru my Router?.

Notes;
1.) I have a successfully running Q-See system now using four cameras, I view this system remotely.
2.) I am using ADSL thru the local Phone Company.
3.) I use a Linksys Modem WRT54G2 (there are two (2) spare ports on the Router.)
4.) I resolve the dynamic address thru TZO software.
5.) The ports are forwarded appropriately
6.) I need four more cameras but do not want to junk my existing four camera system
Thank you for any help on this. :confused:
....Ernie Fearon