Hello,
It sounds like your ideal solution would be a single dock that supports all three 4kp60 displays? If you go to our website and search through the product list, you can select minimum resolution of 4K and minimum monitors supported of 3.
Here's a direct link to that search, for your convenience:
https://www.displaylink.com/products...840x2160&num=3
Hope that's helpful. If not, you can just change the minimum supported monitors to 1 and then go from there, if you want to stick with your original idea.
Kind regards,
Andrew