...clusters of men in formal clothes.

一群群身着正装的男人

There's no town here, just a cluster of shops, cabins and motels at the side of the highway. [+ of]

这儿没有城镇，只在公路边上有一片商店、小木屋和汽车旅馆。

The passengers clustered together in small groups. [V + together]

乘客们三五成群聚在一起。

The children clustered around me. [V + around/round]

孩子们聚集在我的周围。