You Can Do This Via define the roleId, during page load by session you can pass the rloeid, If a user have role for particular product, then he can open otherwise he can't,for this during create user id you should be paas the roleeid also, and during login the page you can fetch the role id;
there is some code that will be helpfull for you,
string strCurrentRole;
try
{
strCurrentRole = Request.QueryString["RoleId"].ToString();
if (Session["Admin"] == null || strCurrentRole != "11" || Session["Roles"].ToString().IndexOf("11") == -1)
{
Session.RemoveAll();
Response.Redirect("Default.aspx");
}
}
catch
{
Session.RemoveAll();
Response.Redirect("Default.aspx");
}
Edit: Code formatted.