A rotor blade assembly group for an engine with a ring-shaped or disc-shaped blade carrier having multiple rotor blades that are provided along a circle line about a central axis of the rotor blade assembly group, wherein the blade carrier has a carrier section that extends radially inwards in the direction of the central axis with respect to the rotor blades, the carrier section comprises a connection area, at which a stiffening structure with at least two, first and second, stiffening elements is fixedly attached, and the first stiffening element is arranged at a first face side of the blade carrier and the second stiffening element is arranged at a second face side that is facing away from the first face side. The first and second stiffening elements are connected to the connection area of the blade carrier and in addition are connected to each other.