[CentOS] mount NFS share over specific nic?

I have a new server with multiple nics running Centos 6.2 and I'd like to force all NFS traffic over one nic.
We're using FreeNAS to dish out NFS shares and I have different IPs on my 2 nics but how can I get the server to mount the share over one particular nic?
Or is there a better way to do it?

Thanx,

Russell Smithies

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