How to hide one part of URL and redirect it?

[eluser]qpixo[/eluser]
I have URL segment: http://www.site.com/loadContent/contact/4

I want to hide the ID 4 in browser address bar: http://www.site.com/loadContent/contact so users can't see it.

Both contact and 4 are loading dynamically

How can I do that in my code?