Dear DCM experts

I'm developing an analysis pipeline for ERP data involving DCM. I'm first identifying sources (using MSP) and using those locations as inputs to DCM. However, many of the sources that come up are not of interest to my hypotheses; furthermore in the MSP analysis it's not uncommon for more than 10 source clusters to evident (e.g. ~15 in extreme cases). In either scenario, I don't want to construct DCM models with 15 connected sources, nor I believe can DCM practically cope with this. Rather, I would prefer to work on maybe 5 or so sources of interest.

However, if I only model 5 sources in DCM despite knowing that the previous source model explains the EEG data with a far larger number of sources, surely this would invalidate the DCM model? If so, how can I model a small number of connections while maintaining validity? I heard that "hidden sources" can be included in a DCM but my understanding is that these are sources that do not directly contribute to the scalp recordings (only indirectly) and if they are included in the DCM model but not connected, they do not contribute to the model at all. So this doesn't appear to be a solution. Does anyone have any thoughts on how best to manage a situation with a large number of sources?

With gratitude
Chris