Compacting of arbitrarily separated bands: Hilbert transformer

I am doing a project in which I have to implement filters to do multiple
band-pass filtering and then compact the arbitrarily separated bands. I
believe using Hilbert transformers after the filtering would be a good
idea to shift the bands to their required locations. However, this has to
be done in real time, and hence the algorithm has to be fast( I think this
rules out the optimal method?). I am relatively new to the concept, and
would appreciate if anyone could tell me about a suitable algoritm/better
way to do it.