Chromatogram peak detection - bunching vs others?
peak(s) determination tends to be application specific.  There are many heuristics and one usually needs to try and test a lot.

It helps a lot if there is a reliable statistical model for your data. 

One trick is to note that peak is larger than its adjacent neighbors.  Peaks on boundaries can be determined by reflection.

Another issue is the set that you are finding peaks on.  Some data consists of multiple scans that can be averaged to reduce noise. One can also do what you refer to as bunching and bunching has numerous variations such as summing, weighted summing, taking a median and combinations.

Another concern may be strong peaks bleeding into weak peaks or masking them entirely.  Many applications have this bin bias problem and there are ways to approach that which are beyond what can be answered in a simple answer given here.

One can also use thresholds to isolate peaks and again that has many variations.

Usually, a community has conventions on how to approach problems like finding peaks and there is probably some documents that constitute a standard. You might want to look for those.