iMac combine wifi and lan connection?

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http://superuser.com – I have iMac in company connected both lan and wifi, where wifi is for public network & lan is private. is there any configuration to connect both wifi and lan and setup always use wifi, but make exceptions to some server use lan (e.g. svn, intranet)? For now, i can just make wifi with higher priority and disable wifi if i need to connect svn. (HowTos)