The phrase "are clustered in a" is correct and usable in written English.
It can be used to describe the arrangement or grouping of items or entities within a specific context or location.
Example: "The data points are clustered in a specific region of the graph, indicating a trend."
Alternatives: "are grouped in a" or "are gathered in a".
Because most psychiatrists are clustered in a few urban areas, the problem is much worse elsewhere.
Sofia is sightseer-friendly because most of its architectural treasures are clustered in a very compact area.
"Now, more than ever in history, Democrats are clustered in a small number of these urban districts," Professor Chen said in an interview.
Its flowers are unisexual staminate (male) flowers are clustered in a tassel, and pistillate (female) flowers are found in an ear.
It would be interesting to know the names of the hospitals concerned – and whether these appalling practices are clustered in a few places – but the report does not reveal that.
The wings -- connected by corridors that Mr. Smith compares to side streets -- are clustered in a U-shape around a central building that is attached only by its "Main Street" -- a 20-foot-wide corridor -- to the others.
Instead, a handful of basic businesses — a hardware store, dry cleaners and Peter's Market, with a nice selection of meats and fish — are clustered in a compact red-brick plaza on Weston Road.
Two-hundred-plus miles north, several dozen windmills are clustered in a roadside park in Spearman, just past the Hungry Cowboy restaurant upon entering the town from the south on Route 207.
Now, the offices are teeming with more than 100 people, most of whom are clustered in a nine very early-stage startups.
In addition, residues with similar activation energies are clustered in a manner that suggests locally collective motions.
Multiple BPH resistance genes are clustered in a similar way to blast resistance genes (Jena and Kim 2010; Ramalingam et al. 2003).
