Endogamia (endogamy), literally inbreeding (marrying within the extended family or local community), is widely used in Spain to refer to favouring people from one's own group over others. It's very commonly used in universities to refer to appointing candidates to teaching posts from within the university rather than from outside. In politics, I think the neatest and most idiomatic way of expressing essentially the same idea is cronyism. It's the idea of favouring people who are "one of us". In a sense it could be described as tribalism, though in politics that can have other connotations.

"Cronyism is the practice of partiality in awarding jobs and other advantages to friends, family relatives or trusted colleagues, especially in politics and between politicians and supportive organizations."
https://en.wikipedia.org/wiki/Cronyism

I don't think you need to translate "comportamiento" separately if you use this; "cronyism" covers the whole phrase.

--------------------------------------------------
Note added at 47 mins (2019-04-14 11:08:25 GMT)
--------------------------------------------------

Sí, sería muy adecuado para esa situación:

"A major publisher of scholarly medical and science articles has retracted 43 papers because of “fabricated” peer reviews amid signs of a broader fake peer review racket affecting many more publications. [...]
With researchers increasingly desperate for recognition, citations and professional advancement, the whole peer-review system has come under scrutiny in recent years for a host of flaws and irregularities, ranging from lackadaisical reviewing to cronyism to outright fraud."
https://www.washingtonpost.com/news/morning-mix/wp/2015/03/2...