Menu links

Hey,
I made one parent page and a lot of subpages. And made a dropdown menu out of it.
The parent page is empty and i want to use it just as a placeholder, because i then get a nice linke. For instance, i get the link parent/item1 .
Now how can i restrict any access to the parent page so the user cant open it by clickin it or using a direct link to it?

Or can you do the same thing in some other way?
Since wordpress creates links depending on the names of your pages i want to have word in the link that defines where the user is at.
For example if he is in the product page it would be webpage/product/item1.

Even though the “product” page does not exist.

I hope you understand what i want to ask. I saw a lot of posts similar to this, but even if i restrict the access through the menu, anyone can get to that page by just using the link directly to it.

Thanks in advance