Mulwan with wan1 only for a host

[Emanu]

Hi,

mulwan with wan1 only for host 10.1.1.9

Alix 3D1

wifi card ath0 for use  wan1
wifi card ath1 for use  wan2

lan port vr0

Interfaces/

LAN
10.1.1.1/24

WAN1
ipaddr  192.168.1.254/24 (DMZ)
gateway WAN1GW1-192.168.1.1

WAN2
ipaddr  192.168.0.254/24 (DMZ)
gateway WAN2GW2-192.168.0.1

Gateways/

WAN1GW1 (default) Interface=WAN1  Gateway=192.168.1.1

WAN1GW1           Interface=WAN2  Gateway=192.168.0.1

Firewall/rules/lan

1 Route allow LAN single host to WAN1  pass=yes
 proto *
 Source      10.1.1.9  Port *
 Destination *         Port *
 Gateway     WAN1GW1

2 Default allow LAN to any rule        pass=yes
 proto *
 Source      *         Port *
 Destination *         Port *
 Gateway     WAN2GW2

my purpose ok
for pc/host 10.1.1.9 traffic is to WAN1GW1
for other host traffic is to WAN2GW2

problem unexpected.
Traffic from WAN2 slows traffic WAN2 end traffic from WAN1 slows traffic WAN1.
when starting speed test from 10.1.1.9 and other host crashes and restarts when traffic from another host ends.
Because if the traffic is separated by two gateways?

Thank you for any help.