Nimbostratus
EmployeeI am not sure if I understood you well but here it is my guess. From the F5 point view should be very simple, you have an IP which is your virtual server and your entry point for your applications. If xyz.com point to your VS then this will be forwarded to the pool in your VS maintaining all the http headers untouched (by default). If you happen to have abc.com pointing to the same virtual server it will happen the same so if your backend servers support contexts it will work just fine.
Different is if you need to rewrite headers, etc... for that you will need irules or LTM policies. LTM policies are around 20% more efficient than irules and cover a lot of simple tasks, I recommend you to have a look as they are very simple. For advanced stuff you have the irules.