Craig Clifton, Raygen Merchant, Robert Wagstaff, William Lindsay (also known as Brown), Daniel Barclay and Ross McColm all died at Polmont Young Offenders’ Institution, near Falkirk.
However, it has emerged that out of 11 deaths at Polmont since 2005, fatal accident inquiries (FAI) determinations have been published in only three cases.
In the other three cases an investigation found that determinations were suppressed from the public at the sheriff’s discretion.
The revelations follow recent publicity about Glasgow University student Katie Allan, 21, who was found dead at Polmont in June, and Dionne Kennedy, 19, who was found dead at Cornton Vale prison.
Families, lawyers and campaigners are calling for the Scottish Government to hold an immediate inquiry.
One mother, June Watt, claimed she had been paid £15,000 halfway through FAI proceedings in court in 2006 in exchange for signing a non-disclosure agreement following the death of her son Craig Clifton, 19. He died in 2005 after suffering three days of diabetic failure but by the time he was taken to hospital his condition had deteriorated and he died.
The Scottish Prison Service (SPS) has denied the “hush money” claim.
Ms Watt said: “Nothing is happening at Polmont because the management are more interested in covering up failings than taking responsibility for them and ensuring mistakes don’t happen again.”
Grandmother Donna Watt described the FAI into her grandson Raygen Merchant’s suicide at Polmont as “one big cover-up”.
Raygen died in 2014, two months before his 18th birthday.
An FAI determined his death was “unforeseeable” despite claims the teenager had been targeted by a number of prison officers.
Cross-party politicians have united in calling for action over Polmont.
Labour justice spokesman Daniel Johnson said: “Humza Yousaf, Justice Secretary, must now initiate a full review to uncover the truth behind these tragic incidents.”
An SPS spokesman said Ms Watt’s case had been settled out of court in a civil action and that “no conditions were attached to it.
“Healthcare was the responsibility of the SPS at this time.
“The SPS settled an action for loss of society. We do not place conditions on such settlements.
“We have never had CCTV in cells. We have CCTV in other locations, which is only retained for a limited time.”
A Scottish Government spokesman said: “As the First Minister made clear this week responding to the deaths in custody of two young people, we are determined that any lessons that need to be learned will be learned and that all appropriate agencies must look closely at what happened.
“The First Minister also confirmed that issues such as secure care provision, mental health support in Polmont and how we can keep more young people out of the criminal justice system would be considered.”