The present invention involves traffic management in a communication system (1) comprising multiple communication terminal (10, 200) that each has data flows presented in transmit buffers (14, 220). The terminals (10, 200) utilize a default priority scheme for selecting data from the buffers (14, 220) to transmit at transmission occasions determined by a schedule scheme. A switching event is detected based on information of an estimate distribution of data flows in a first portion (2) of the system (1). A priority scheme update message is generated based on this event detection. The update message comprises information of a temporary priority scheme that is to be used by terminals (10, 200) in a second portion (2; 5) of the system (1). By using this temporary scheme that assigns new temporary priorities to the data flows, a local shaping of the transmission pattern and data flow distribution in the second system portion (2; 5) is possible.