Combined, the schemes cover £21bn (€28.7bn) in assets, and the company, a former government-owned defence manufacture, has more than 200,000 members.
Hymans, the incumbent adviser on three of the seven schemes, beat off competition for the scheme-wide tender from five other firms.
The consultancy will appoint a scheme actuary to each individual scheme, as well as a client-relationship actuary to oversee the relationship with the defence manufacturer.
Hymans will be responsible for advising on the schemes’ strategic approach to risk management, as well as providing a common platform to interlink with investment solutions.
It also provides investment consulting to one of the seven schemes.
Nigel Tinsley, pensions director at BAE Systems Group Pensions, said the one-firm approach was essential for good governance across the seven schemes.
In other news, the UK statistics office has published figures showing that, since the introduction of auto-enrolment, total contributions have increased but median contribution rates have fallen.
The annual amount saved in 2014 across public and private sector workplace pensions was £80.3bn, an increase from £2.6bn in 2013, according to new data released by the Office for National Statistics (ONS).
The contributions were split between 30% contributions from the employer and 60% from employee, with 10% provided through government tax relief.
However, the ONS said there was a “marked decline” in the amount saved per saver in 2014 in the private sector – a likely consequence of an increase in the number of savers contributing at auto-enrolment minimum levels, which are not set to rise above 2% before October 2017.
Malcolm McLean, senior consultant at Barnett Waddingham, said the minimum levels were likely to increase as the phasing-in of auto-enrolment was completed.
However, he said the “inadequate” levels of savings were likely to remain.
“This problem,” he said, “needs to be addressed by the use of some system of auto-escalation of contributions or other means as soon as possible.”