Help in creating a single library by combining/merging other libraries

I have a couple of queries out here before I start creating my custom library to include methods, models, properties, etc which are commonly used by the different in-house applications that my company uses.

Question 1: how can I implement a number of libraries in a class library I am planning to create? The concept is explained below:

Library Setup: I am trying combine the following into one DLL file:

1: Extension Methods

2: Object Relational Model

3: Common Database Queries Used

and wondering if I could call them like the defaults ones: example System.Text.RegularExpressions.Regex(variable), System.String.Join(variable)开发者_JAVA百科 etc.

I want to use the DLL methods, models, queries, etc based on the namespace provided in my various application as follows:

using CompanyLibrary.Extensions;
using CompanyLibrary.Models;
using CompanyLibrary.Queries;

Based on the namespace specified, I can use their members, methods, properties.

I know how to create DLL files for separate Projects that will give me Extensions.dll, Models.dll, Queries.dll.

Main Question: How do I merge all the dll's into a single dll

It sounds like you want to create a single library project with multiple namespaces in different folders.

Are you just looking for ILMerge?