Select the files you want to merge in Process1, and run the process Standardize > Concatenate signals.
I have run this on the subject averaged ERP files. If concatenate is set to one it gives one file with all subject averages but not the group average. Set to 0 it seems to give a separate file for each individual.
Indeed.
If you define the cluster differently for each subject, you can't compute the group average and then extract the cluster time series. You need to extract the cluster for each subject-level ERP separately, to a different file (concatenate=0), and finally average the subject-level cluster signal together to obtain a group-level cluster signal.
If there were a way to average all subject level averaged cluster files for group A and B with one output file that might be easiest?
You can select the files you want in Process1 and call the averaging multiple times, once for each group.
I'm not sure I understand what the problem is here, but probably because I don't manage to picture what intermediate files you get.
If you need further help, please post screen captures illustrating all the files you are dealing with: one subject-level average, both the signal figure and the files shown in the database explorer, same for the group average, the option windows of all the processes you are using and/or the full script, an illustration of what the clusters look like, the problems you have... - Thanks