Multiple Domain Aliases

[rioku]

We send out a lot mailings and I want to test which ones perform
better. My plan is to use different domain aliases to track the
performance.
Example:
Mailing 1: will have example.com as the call to action
Mailing 2: will have sample.com as the call to action

Each of these domains will point (redirect) to the content. Does
anyone know how this can work with Google Analytics. Will they both
show up as direct traffic or will the visits be separated out by URL?



Thanks for your help