Treat them as one W-2.  Although the amounts have been broken down between several Forms w-2, they are but one.  You will enter the Federal amounts as reported on the Federal filing copy, and when you get to boxes 15, 16, 17, 18, 19, and 20, you will put that information into TurboTax from the different sections of the W-2 that reports that income.  Nevertheless, all of the information is for one W-2.  

Note:  The amounts refered to in your question are for local taxes (to a city or a county, for example).  Depending on your local city taxes, you may have a local tax filing requirement.  However, with a few exceptions (OH, MI, and NY), these returns are not included in TurboTax programming.