VS 2010 Filtering Listbox From Combobox

On the form, I have combobox1, combobox2, datagridview, and a listbox. Basically, combobox2 displays a list of street names. My problem is that once the user selects a street name from combobox2, the listbox should be populated with only the customers' names who lives on that street. How can I go about populating a listbox with just the customer names? Originally, the street names include the house numbers as well. For example, "5100 E Dublin Granville Rd". Fortunately, I figured out how to display ONLY the street names ('E Dublin Granville Rd') and not the full street address to the combobox by adding the following public property below. However, I am still encountering a problem because now the combobox has duplicates of the same street name![code]