Hello Dan,
you might want to look into adding route maps to your static NAT entries for your web and email servers as following:
ip nat inside source static 10.10.10.1 212.136.1.1 route-map TO_ISP_1
ip nat inside source static 10.10.10.2 212.136.2.1 route-map TO_ISP_2
ip nat inside source static 10.10.10.3 212.136.3.1 route-map TO_ISP_3
!
access-list 101 permit ip 10.10.10.0 0.0.0.255 212.136.1.0 0.0.0.255.
access-list 102 permit ip 10.10.10.0 0.0.0.255 212.136.2.0 0.0.0.255
access-list 103 permit ip 10.10.10.0 0.0.0.255 212.136.3.0 0.0.0.255
!
route-map TO_ISP_1 permit 10
match ip address 101
set ip next-hop X.X.X.X (next hop for ISP 1)
!
route-map TO_ISP_2 permit 10
match ip address 102
set ip next-hop Y.Y.Y.Y (next hop for ISP 2)
!
route-map TO_ISP_3 permit 10
match ip address 103
set ip next-hop Z.Z.Z.Z (next hop for ISP 3)
!
interface Serial1/0
description T1 Link To ISP_1
ip address X.X.X.X A.A.A.A
ip nat outside
!
interface ATM0/1
description DSL Link To ISP_2
ip address Y.Y.Y.Y B.B.B.B
ip nat outside
!
interface ATM1/0
description DSL Link To ISP_3
ip address Z.Z.Z.Z C.C.C.C
ip nat outside
!
interface FastEthernet0/1
ip address 10.10.10.254 255.255.255.0
ip nat inside
Obviously the IP addresses used are likely not yours, but you get the concept.
Can you try this and see if it works ?
Regards,
GP