A system for grouping extracted ion chromatogram peaks of two or more product ions of a known compound, comprising: a separation device that separates a known compound from a sample mixture; a mass spectrometer that performs at each retention time of a plurality of retention times one or more mass spectrometry/mass spectrometry (MS/MS) scans on the separating sample mixture using one or more sequential mass window widths in order to span an entire mass range, producing a collection of product ion spectra for the entire mass range for the plurality of retention times; and a processor configured to: receive the collection of product ion spectra for the entire mass range for the plurality of retention times, select M product ions of the known compound, calculate an XIC for each of the M product ions from the collection of product ion spectra, producing M XICs, subtract each XIC of the M XICs from each of the other M XICs, producing M 2 subtraction curves, wherein each subtraction curve is calculated from a first XIC and a second XIC by, at each retention time, normalizing an intensity of the first XIC at the each retention time and two or more intensities of the first XIC at two or more adjacent retention times, normalizing an intensity of the second XIC at the each retention time and two or more intensities of the second XIC at the adjacent retention times, subtracting the normalized intensities of the second XIC from the corresponding normalized intensities of the first XIC, and calculating a statistical measure of the difference intensities, identify one or more regions of one or more retention times where one or more subtraction curves of the M 2 subtraction curves have values that are within a threshold value of zero, and for each region of the one or more regions, obtain two or more XICs used to calculate the one or more subtraction curves identifying the region and adds each peak of the two or more XICs that is in the region to a peak group. a separation device that separates a known compound from a sample mixture; a mass spectrometer that performs at each retention time of a plurality of retention times one or more mass spectrometry/mass spectrometry (MS/MS) scans on the separating sample mixture using one or more sequential mass window widths in order to span an entire mass range, producing a collection of product ion spectra for the entire mass range for the plurality of retention times; and a processor configured to: receive the collection of product ion spectra for the entire mass range for the plurality of retention times, select M product ions of the known compound, calculate an XIC for each of the M product ions from the collection of product ion spectra, producing M XICs, subtract each XIC of the M XICs from each of the other M XICs, producing M 2 subtraction curves, wherein each subtraction curve is calculated from a first XIC and a second XIC by, at each retention time, normalizing an intensity of the first XIC at the each retention time and two or more intensities of the first XIC at two or more adjacent retention times, normalizing an intensity of the second XIC at the each retention time and two or more intensities of the second XIC at the adjacent retention times, subtracting the normalized intensities of the second XIC from the corresponding normalized intensities of the first XIC, and calculating a statistical measure of the difference intensities, identify one or more regions of one or more retention times where one or more subtraction curves of the M 2 subtraction curves have values that are within a threshold value of zero, and for each region of the one or more regions, obtain two or more XICs used to calculate the one or more subtraction curves identifying the region and adds each peak of the two or more XICs that is in the region to a peak group. receive the collection of product ion spectra for the entire mass range for the plurality of retention times, select M product ions of the known compound, calculate an XIC for each of the M product ions from the collection of product ion spectra, producing M XICs, subtract each XIC of the M XICs from each of the other M XICs, producing M 2 subtraction curves, wherein each subtraction curve is calculated from a first XIC and a second XIC by, at each retention time, normalizing an intensity of the first XIC at the each retention time and two or more intensities of the first XIC at two or more adjacent retention times, normalizing an intensity of the second XIC at the each retention time and two or more intensities of the second XIC at the adjacent retention times, subtracting the normalized intensities of the second XIC from the corresponding normalized intensities of the first XIC, and calculating a statistical measure of the difference intensities, identify one or more regions of one or more retention times where one or more subtraction curves of the M 2 subtraction curves have values that are within a threshold value of zero, and for each region of the one or more regions, obtain two or more XICs used to calculate the one or more subtraction curves identifying the region and adds each peak of the two or more XICs that is in the region to a peak group.