It is still probably a good idea to setup a unique profile for each sub domain, especially if the web content on each sub domains belongs to different business stakeholders.
To setup unique profiles for each sub domain within Google Analytics you will need to create a new profile for each sub domain and then only include the analytic data from that sub domain.
Create a New Profile
- Click on the "Add New Profile" link.
- Select the "Add a Profile for an existing domain" radio button and enter a Profile Name that can be easily identified to the sub domain before clicking on the Finish button.
- Click on the "Filter Manager Link" and then the "Add Filter Link".
- Enter a filter name that can be easily identified to the sub domain, select the radio buttons "Custom Filter" and "Include" and under the Filter Field dropdown menu select "Hostname".
- In the Filter Pattern field type in the subdomain you are creating this profile for followed by a backslash that is immediately followed by a period, then type in the root domain followed by another backslash and period and then type in the top level domain suffix of your website (such as .com, .net, org, etc). Hence, your Filter Pattern should look something like this analytics\.rwebconsulting\.com.
- Under the Available Website Profile list, select the profile you created in Step 1 and click on the Add button and then the Save Changes button