You can config custom queue on the 7609 router on the outside interface to control the bandwith of two clients. each client share 50% bandwidth
I assmue that your client 1 ip address 1.1.1.1 client 2 ip address 2.2.2.2
access-list 1 permit 1.1.1.1
access-list 2 permit 2.2.2.2
queue-list 1 protocol ip 1 list 1
queue-list 1 protocol ip 2 list 2
queue-list 1 queue 1 byte-count 1000
queue-list 1 queue 2 byte-count 1000
interface serial 0
custom-queue-list 1
Here is a link how to do it:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/qos_c/qcprt2/qcdcq.htm
Best Regards,