One of the units, called Engine PR & Activation and headed by Engine group MD Simon Peck, will include MHP and Mischief, as well as sports marketing agency Synergy and events consultancy Slice.
Engine said 56 per cent of its revenue comes from clients using multiple agencies.
"Each of Engine’s agency and consultancy brands will now sit within one of these business units, encouraging even closer collaboration and integration of Engine’s specialist expertise," the company said today.
"By bringing complementary businesses together, Engine will look to combine different areas of specialist expertise to develop new products, propositions and ways of working."
The individual agency and consultancy brand names will be retained, Engine said.
Debbie Klein, CEO of Engine Europe and Asia Pacific, said: "Since its inception, Engine has led the way in seamlessly delivering integrated marketing communications. We’ve always been client-led in our approach, building bespoke teams around business needs. By bringing our market-leading brands together into four connected business units, we will be able to further leverage the collective firepower of our specialists whilst continuing to value and protect their distinctiveness."
The other three business units announced today are: Engine Creative & Content; Engine Digital, transformation, data and insight; and Engine Media. All will be led by a member of the Engine senior leadership team.
In April, PRWeek’s sister title Campaign reported that Engine is eyeing a possible sale of the agency group, less than three years after buying it.