Can I use two projects in same solution in Visual Studio using c#

I am trying to use two projects in same solution one is based on MVC and another is based on 3 Layer Architecture using C# and both of the projects are connected to each other. Is it possible anyone please tell me? My first project is Website which is based on MVC and Second one is Web-based software i want to make this software in 3 Layer architecture after that i will connect this 3 layer software with my MVC website.