FHi, the brainchild of the agency's head of innovation Eva Keogan, comprises a 45-strong team of existing staff, each of whom will act as a 'platform tsar' for social media sites such as Facebook or Foursquare.
These staff members will serve as focal points for queries relating to their allotted sites, both within the organisation and for clients.
Keogan said she pitched the idea to Fishburn Hedges bosses during her interview in January.
'We have a successful 21-year history, but we need to change to stay ahead of the pack,' she said.
'Social media have been a game changer. Digital agencies are growing and it is an opportunity for us to grow as well.'
Keogan added that the unit was 'not a standalone department but a way of working across the organisation'.
The unit is launching a suite of products and services marketed under the FHi brand, such as social and digital masterclasses, and new techniques for auditing.