Tcp/ip session based routing

Hi,


My ADSL provider in Brazil give us a link with a limit of 30 tcp/ip
sessions. So, for a especific use, I will buy another link with the 30
limit but lesser bandwidth. But how to tell linux to only use second
link when first is full (30 limit reached)?


Or, how to use the two links in a better way than the below command?


ip route add default scope global \
nexthop via $gw1 dev $dev1 weight 3 \
nexthop via $gw2 dev $dev2 weight 1


Thank you
Tom