The phrase "a group of reports" is correct and usable in written English.
It can be used when referring to multiple reports that are being considered or analyzed together.
Example: "The committee reviewed a group of reports to assess the project's progress."
Alternatives: "a collection of reports" or "a set of reports."
A group of villages reports hierarchically to a group village headman who then reports to the chief of the traditional authority.
In the 9 December Physical Review Letters, a group of physicists reports taking this strategy a step further, to test whether a cat is both dead and alive.
A group of researchers reports that the brain structure responsible for fear reacts more strongly to pictures of terrified faces than to the scary images themselves.
A group of respondents reported that they understood half or less than half of the feedback report (variable 1), yet found the report useful (variable 2).
The way Libor works is a group of banks report what they're being charged to borrow at short terms, and then those reports are used to set Libor every day.
This month, in the New England Journal of Medicine, a group of oncologists reported the success of such a strategy with C.L.L.
In March, a group of Eritreans reported the matter to the police and sent a dossier of allegations to the Met commissioner, Sir Bernard Hogan-Howe.
In 1985, a group of scientists reported on a brain-damaged subject who could recall everything but the names of fruits and vegetables.
Also on Monday, a group of scientists reported that global carbon emissions, which had been flat for the past few years, were once again on the rise.
Writing in The Journal of the American Academy of Dermatology, a group of researchers reported that they sought out volunteers who regularly went to tanning salons and invited them to lounge in tanning beds at no charge over a period of six weeks.
