Multiple NICs - Only one active at any one time

[Miles]

I have a laptop with two NIC's, one wired (eth0) and one wireless (eth1). Only one of them will be plugged in at anyone time. The problem is that on boot up the system attempts to start them both. One will fail and then other network services won't start because of the failed 'net' dependency.

A search on the forums has come up with this post:
https://forums.gentoo.org/viewtopic.php?t=14607

Which points to this doc:
http://www.gentoo.org/doc/rc-scripts.html#doc_chap2

It's suggested solution is a bit vague and I was wondering if any one has actually achieved this.