My question is can the pix send traffic out through the same interface it received the traffic on? I'm currently using pix os version 6.2.
No Dan not with that version of PIX OS, you need to upgrade to the 7.x or 8.x and also note that you may need more memory to accomplish when you upgrade you want to enable the command:
CYPHER(config)# Same-security-traffic permit ?
configure mode commands/options:
inter-interface Permit communication between different interfaces with the
same security level
intra-interface Permit communication between peers connected to the same