GridView with a Many to Many Datasource

Question

I am having a problem achieving something. I have a Gridview. In the Gridview will be books. Now, books and authors have a many to many relationship, so you cannot just use an SQLDataSource with a JOIN query, as you will end up with multiple rows for the one book (one for each author).
I figured using the ObjectDataSource would be my best bet.

I created an ObjectDataSource. The SelectMethod for that ObjectDataSource is a method that returns an array of books i.e. Book[] . Within each Book  object in that array is a generic list of authors i.e. List<Author>. The challenge is, somehow accessing the properties of those Authors to output in the relevant cells of the GridView. That is where I am stuck. Here is a bit of markup to give you an idea (the 2nd column template is the one to scrutinise):
           
        <asp:GridView ID="titles" runat="server" AllowPaging="true" AllowSorting="true"
                AutoGenerateColumns="False" DataSourceID="PubsDS" EnableViewState="False"                 
                 OnRowCreated="titles_RowCreated" OnSorting="titles_Sorting"
                 OnPreRender="titles_PreRender" DataKeyNames="ISBNNr">            
            <Columns>
                <asp:TemplateField HeaderText="Title" SortExpression="Title">
                    <ItemTemplate>
                        <asp:HyperLink id="titleItemLink" runat="server"
                            NavigateUrl='<%# Eval("ISBNNr", "item.aspx?title_id={0}") %>'
                            Text='<%# Eval("Title") %>'>
                        </asp:HyperLink>
                    </ItemTemplate>
                    <ItemStyle  CssClass="w200" />
                    <HeaderStyle CssClass="w200" />
                    <FooterStyle CssClass="w200" />                   
                </asp:TemplateField>  
                <asp:TemplateField>
                    <ItemTemplate>
                        <asp:HyperLink runat="server" ID="tester"
                            NavigateUrl='<%# Eval("Authors") %>'
                            Text='<%# Eval(Authors) %>'>
                        </asp:HyperLink>
                    </ItemTemplate>               
                </asp:TemplateField>                                
                <asp:BoundField DataField="ISBNNr" HeaderText="ISBN" SortExpression="ISBNNr" />
               <asp:HyperLinkField DataNavigateUrlFields="ISBNNr" DataNavigateUrlFormatString="item.aspx?title_id={0}"
                    DataTextField="ISBNNr" DataTextFormatString="more information"  HeaderText="Item Information" />
            </Columns>
        </asp:GridView>