A multistage combining sub-system for a distributed antenna system (“DAS”) is disclosed. The combining sub-system can receive broadband uplink signals from remote units of the DAS. The sub-system can divide the received broadband uplink signals into sets of narrowband uplink signals. The combining sub-system can select subsets of narrowband uplink signals from the sets of narrowband uplink signals. The subsets can be selected based on the narrowband signals in the subsets having a signal characteristic indicative of useful information. The combining sub-system can combine the selected subsets of narrowband uplink signals for routing to a base station. Combining the selected subsets of narrowband uplink signals can involve excluding narrowband uplink signals that are not included in the selected subsets of narrowband uplink signals.