No built in way to do it. But you can control the visibility of the dropdown menu items via custom css.
Here is a sample dropdown that shows an item for logged in users and a different item for guests.
<li class="loggedin"><a href="https://somelink.com">visible to logged in users</a></li>
<li class="guest"><a href="https://otherlink.com">visible to guests</a></li>
Once you create a dropdown like that you can control the visibility via custom css. The body element is given a class based on the user's logged in status. user-loggedin
if they are logged in and user-guest
if they are logged out.
So in your custom css you can use those classes.
#main-nav .dropdown-menu .loggedin, #main-nav .dropdown-menu .guest {
display: none;
}
body.user-loggedin #main-nav .dropdown-menu .loggedin {
display: block;
}
body.user-guest #main-nav .dropdown-menu .guest {
display: block;
}