Sadiq Bendriss, 20, and Kurrin Bendriss, 19, were sentenced to eight years in jail this week after they pleaded guilty to robbery and possession of an imitation firearm, the London Evening Standard reported Friday.
Lamin Joof, 21, was sentenced to seven years in jail on similar charges and Russell Aljaf, 20, is due to be sentenced by Harrow Crown Court after pleading guilty to conspiracy to commit robbery, burglary and possession of an imitation firearm.
A fifth suspect is scheduled to go on trial next year.
Police said the men hailed taxis on three occasions beginning in March of this year to commit gunpoint robberies at hotels and target people on the streets.
The men were arrested when a driver contacted police while the men were burglarizing a home.
"I am really pleased that this gang is off London's streets and no longer able to carry on committing these robberies," Detective Constable Rob McGhee said. "The level of violence and the disturbingly blatant way they carried out these crimes clearly demonstrated they had no regard for the law."