Learn English – “Gain in popularity” vs “Gain popularity”

The best word for this idea depends on the context.

Within a company: As you allude to in your question, branch is appropriate for referring to other offices within the same company. To distinguish colleagues by role rather than location, you can use department or division. Many companies will have additional local jargon along those lines, like job function, organization, role, or silo.

Generally: For people who don't (necessarily) work for the same company, you can talk about different fields, industries, sectors, or specialties, depending on the nature of the difference. For example, industry and sector generally refer to very broad categories like finance, government, manufacturing, military, and non-profit, whereas field and specialty usually refer to different roles within the academic, engineering, and scientific sectors.

There are some senses of "much" and "many" that are restricted to non-affirmative contexts, and when "much" and "many" are used in that way then they are negatively-oriented polarity-sensitive items (NPIs).

There are some senses of "much" and "many" that can be used in positive affirmative environments, but then those instances of "much" and "many" are not NPIs.

And then, to make things even more confusing, some words (such as "much" and "many") may be an NPI in some styles or registers and not in others.

This issue with "much" and "many" is discussed in the 2002 CGEL, pages 823, 826-7. There might be some related info about NPIs on the internet, such as in wikipedia or on linguistics sites, but you've gotta be careful of info found on the internet.

If you want more info here in this post, then leave me a comment and I'll try to come back later tonight. (The reason why this post is now so brief is that many topics are involved and I'll have to discuss them as a foundation for this topic that you are asking about.)

Note that CGEL is the 20002 reference grammar by Huddleston and Pullum et al., The Cambridge Grammar of the English Language.