It is presented a method for controlling uplink contribution from a plurality of remote radio heads in a combiner. The method is performed in a remote radio head controller and comprises the steps of: determining a first set of at least one remote radio head; determining a second set of at least one remote radio head, wherein the first set and the second set are disjoint; selecting a first uplink carrier for a first wireless device; selecting a second uplink carrier for a second wireless device; and applying a configuration such that the at least one remote radio head of the first set refrains from contributing on a first channel with uplink signals on the second uplink carrier and that the at least one remote radio head of the second set refrains from contributing on the first channel with uplink signals on the first uplink carrier.