Rivergum is one of just two North Metro Cricket Association sides through to the elimination finals of the Northern Region T20 competition.
The Cobras are the other NMCA team through, in a competition dominated by teams from the Diamond Valley Cricket Association.
Rivergum won through with victory over South Morang.
The Kookas made 6-145 from their overs, before restricting South Morang to 3-111.
The Kookas finished second behind Epping in group nine, but got through to the finals as one of the six next best teams.
Epping made it three wins with victory against Mernda.
Epping made 7-115 on the back of 75 not out from Andrew Bennett, before bowling Mernda out for 110, with Hussain Hanif taking five wickets.
Also in the finals is Bundoora, which made a clean sweep of its pool games with victory against Preston Baseballers.
Asharn Hodge made 64 at the top of the order for the Bulls as they made 6-145. Preston Baseballers could only manage 9-99 in reply.
Last season’s Northern Region T20 runners-up Lalor Stars are again through to the finals having finished on top of group five. Old Paradians, which finished second behind the Stars, is also through to the next stage.
Rosanna, Heidelberg, Research Eltham Collegians, Macleod, Riverside, Plenty, Cobras, Lower Eltham, Lower Plenty, Banyule and Montmorency are the other teams through to the elimination finals.