1. A method performed by a master node for handling connections to slave devices, which connections are Bluetooth connections, and which master node and slave devices operate in a Bluetooth communication system, the method comprising:allocating to a first group of slave devices a first set of channels;
allocating to a second group of slave devices a second set of channels where the first set of channels relates to a first part of a frequency band supported by the master node and the second set of channels relates to a second part of the frequency band that is different from the first part of the frequency band;
assigning to the first group a first connection, between the master node and a first slave device, to use channels comprised in the first set of channels;
attenuating, using a first filter, for the first connection in the first group, signals relating to any other group of slave devices being allocated a set of channels, including the second group;
assigning to the second group a second connection, between the master node and a second slave device, to use channels comprised in the second set of channels; and
attenuating, using a second filter, for the second connection in the second group, signals related to any other group of slave devices being allocated a set of channels, including the first group;
wherein the master node includes one or more antennas each connected to at least one of a first antenna and a second antenna.