Multiple selections in listbox to create separate records in table

[jumbledore]

I am trying to create a form based database to store links to various pdf documents. These files belong to one or multiple projects. So I have created a form with a list box which shows the various projects and and a text box which has the link to the pdf but the problem is when multiple projects are selected the information is not stored in the table as separate records. How should I go about doing this? For example if one pdf file refers to 2 projects X & Y and if a user selects these 2 projects in the list box and enters the path of the pdf in a textbox it should create 2 records in the table:

Project	Path
X	C:/Sales/X
Y	C:/Sales/Y