The Priority One group has about 300 members and a more political focus on getting younger people engaged with local politicians on issues relevant to helping the city and the region develop, said Greg Simmonds, Priority One's strategic projects manager.
"It helps get young professionals together with elected members and participate in workshops so they can have a say and put their ideas forward," Mr Simmonds said.
"Essentially, it makes sense to merge so there's one young professionals group for people to network in and advocate for things that are important to young people in the city."
Both groups believe there has been some duplication of membership and cross-over between the groups, which will be clarified once the membership lists are consolidated.
Rocket is largely supported by sponsorship from local businesses to provide venues for social events and presentations and charges on an event-by-event basis, with some being free. Mr Eagleson said the new entity would be able to draw on appropriate resourcing from both former organisations. "At the moment we have two different organisations essentially doing the same thing, but with different angles on it," he said.