A hearing device for improving a hearing impaired user's ability to perceptually separate a target sound from competing sounds, the target sound and the competing sounds forming a composite sound signal having a given frequency range, the hearing aid comprising • an input unit for providing a time-domain electric input signal y(n) as digital samples representing said composite sound signal in a frequency range of operation forming part of said given frequency range, n being a time-sample index, • an analysis filter bank subdividing said frequency range of operation, or a part thereof, of said composite sound signal into a plurality of frequency sub-bands and providing corresponding frequency sub-band signals; • a signal processing unit connected to said analysis filter bank and comprising ∘ a band grouping unit for arranging frequency sub-bands in sub-band-groups based on comparable characteristics among the plurality of frequency sub-band signals; ∘ an envelope extraction unit for calculating a group envelope for each of said sub-band groups, said group envelope comprising peaks and troughs; ∘ an enhancement unit for providing an enhancement function for each sub-band group configured to enhance said peaks in the group envelope and/or attenuate said troughs in the group envelope; and ∘ a combination unit for multiplying a signal in the frequency sub-bands of each individual sub-band-group by a respective enhancement function for the sub-band group in question, or a scaled version thereof, to provide enhanced frequency sub-band signals. • an input unit for providing a time-domain electric input signal y(n) as digital samples representing said composite sound signal in a frequency range of operation forming part of said given frequency range, n being a time-sample index, • an analysis filter bank subdividing said frequency range of operation, or a part thereof, of said composite sound signal into a plurality of frequency sub-bands and providing corresponding frequency sub-band signals; • a signal processing unit connected to said analysis filter bank and comprising ∘ a band grouping unit for arranging frequency sub-bands in sub-band-groups based on comparable characteristics among the plurality of frequency sub-band signals; ∘ an envelope extraction unit for calculating a group envelope for each of said sub-band groups, said group envelope comprising peaks and troughs; ∘ an enhancement unit for providing an enhancement function for each sub-band group configured to enhance said peaks in the group envelope and/or attenuate said troughs in the group envelope; and ∘ a combination unit for multiplying a signal in the frequency sub-bands of each individual sub-band-group by a respective enhancement function for the sub-band group in question, or a scaled version thereof, to provide enhanced frequency sub-band signals. ∘ a band grouping unit for arranging frequency sub-bands in sub-band-groups based on comparable characteristics among the plurality of frequency sub-band signals; ∘ an envelope extraction unit for calculating a group envelope for each of said sub-band groups, said group envelope comprising peaks and troughs; ∘ an enhancement unit for providing an enhancement function for each sub-band group configured to enhance said peaks in the group envelope and/or attenuate said troughs in the group envelope; and ∘ a combination unit for multiplying a signal in the frequency sub-bands of each individual sub-band-group by a respective enhancement function for the sub-band group in question, or a scaled version thereof, to provide enhanced frequency sub-band signals.