IP Forwarding (Routing) thru 2 Cisco 2600's

[Stormfollower]

What I've got:

ISP->Switch->Microwave T1 <-> Microwave T1->Switch->Static IP xx.xx.xx.8 (VOIP device)

What I'd like to do (if possible):

ISP->Switch->Microwave T1 <----> Microwave T1->Switch---> (1)
|------> (2)
(1)->Static IP xx.xx.xx.8 (VOIP device)
(2)->Cisco 2600 FastEthernet 0/0 -> Serial 0/0 -> Microwave2 T1 <--> Microwave2 T1->Cisco 2600 Serial 0/0 -> FastEthernet 0/0 -> Static IP xx.xx.xx.4 (VOIP device)

The two VOIP devices are on the same IP subnet and are route-able IP's.

If I understand things, the FastEthernets need to be route-able IP's. The two Serial ports can be non-route-able.

I have connected devices through 2 2600's using the following, but can't wrap my mind around how to do what I want w/o having more than the two static IP's xx.xx.xx.8 and xx.xx.xx.4:
Current configuration : 695 bytes
!
version 12.1
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname xx-50
!
!
!
!
!
!
ip subnet-zero
no ip finger
!
!
!
!
interface FastEthernet0/0
ip address 10.1.200.3 255.255.255.0
no ip route-cache
no ip mroute-cache
speed 100
full-duplex
no cdp enable
!
interface Serial0/0
ip unnumbered FastEthernet0/0
encapsulation ppp
no ip route-cache
no ip mroute-cache
service-module t1 clock source internal
service-module t1 timeslots 1-24
no cdp enable
!
ip classless
ip route 0.0.0.0 0.0.0.0 Serial0/0
no ip http server
!
no cdp run
route-map rtr permit 10
!
!
line con 0
transport input none
line aux 0
line vty 0 4
login
!
end

Any help is appreciated.