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

interface