The phrase "are mainly organized" is correct and usable in written English.
It can be used to describe the primary method or structure by which something is arranged or classified.
Example: "The events are mainly organized by theme, allowing participants to choose sessions that interest them the most."
Alternatives: "are primarily arranged" or "are chiefly structured".
The LEE comprises 41 genes that are mainly organized in five operons.
His areas of research are mainly organized around the economic and social analysis of middle-income countries in Latin America.
The Irish armed forces are mainly organized around their external mission; however, they do play a residual role in what they call "on-island" security.
Given that the rest of the parties are mainly organized in a single cluster, this dual structure confirms the different behavior of Barcelona en Comú when discussing with other political parties.
It is clear to see that the samples are mainly organized according to the experiment to which they belong.
NB-encoding genes are unevenly distributed in the plant genome and are mainly organized in multi-gene clusters.
In particular the analysis of the main spectral parameters, namely the G and D band position and widths as well as the I(D /I(G) ratio, elucidates that the sp2-bonded phase featuring soot particles resulted to be mainly organized in clusters of nanometric size with some presence of sp2 olefinic chains.
This exhibition was mainly organized by the Kanagawa Prefectural Government, and Professor Itoh was a core member of the exhibition committee [8].
This concept is mainly organized in a decentralized way since each instance has to be set up by a user without having a central unit.
The course considered for this study was mainly organized around lecture classes in which students were guided through the essential concepts about health, health promotion, disease prevention, and predictors for disease.
