You need to use policy based routing for that, but first, you need to create new interfaces and bind your tunnels to those interfaces:
Interfaces -> (assign)
Once that is done, it will create new gateways which can then be used in your LAN firewall rules.
For example, if you want a client with an IP of 10.0.0.1 to be routed over a certain interface, you'd create a new LAN rule above your any/any, change the source to 10.0.01:
[image: 2017-01-01%2011_26_13-pfsense.gilbert.home%20-%20Firewall_%20Rules_%20Edit_zpshbibdsy0.png]
then in the "Extra Options" section, click the "Display Advanced" button, scroll down to the bottom and change the Gateway:
[image: 2017-01-01%2011_29_43-pfsense.gilbert.home%20-%20Firewall_%20Rules_%20Edit_zpsc1ttifpn.png]
Now all internet traffic sourced from 10.0.0.1 will be routed over the tunnel assigned to that particular gateway.
*** The one gotcha that I've read is that you need to bounce the tunnels after the interfaces are assigned or traffic will not be routed properly. So, Status -> Services and restart the service for each tunnel you assigned to your interfaces***