Unfortunately, there are no laws in place that protect workers from generally bad treatment that is not based on an illegal reason. The term "hostile
work environment" comes to us from the Supreme Court of the United States. It is a very specific term. Though it certainly sounds like it would apply in your situation, the high court required another ingredient beyond the types of things you are talking about here.
Hostile work environment is illegal harassment (ingredient 1) which is based on your race, religion, gender, age, disability or FMLA
use (ingredient 2). Without that second factor, there can be no hostile work environment. This is because the Supreme Court stated that our employment laws
are not meant to be a civility code, but are only meant to deal with illegal discrimination
I do note that you feel this is unlawful treatment, but the list that I have outlined are the forms of discrimination that are actually illegal. Race, religion, gender, age, disability or FMLA use. Treating people differently based on just a personal dispute
of personalities, while very unprofessional, is not illegal discrimination because there is no statute that makes it illegal.
Now, some states have considered passing workplace dignity laws that might apply in situations where the harassment in generalized and not specifically directed at or based on a discriminatory factor like race or age. Unfortunately, no state has managed to pass such a law at this time.
You have done the right thing by bringing this to the attention of the Branch Manager. What I would also suggest you do is think about and document going back as far back as you can remember all of the relevant events related to this matter. So when you meet with the manager you have a clear concise conversation. Ultimately if the organization is not going to do anything about it, you should consider other employment options. because life is too short to have to deal with toxic people like this.
I believe this answers your question. However, if you need clarification or have follow-up questions regarding this matter, I will be happy to continue our conversation – simply reply to this answer. If you are otherwise satisfied with my response, please leave a positive rating as it is the only way I am able to get credit for my answers. Thank you, ***** ***** wish you all the best with this matter.