Noise covariance for each sub-folder

Hi,
I have a question concerning loading covariance matrices.
I have one subject called group analysis. I have some common files: the channel file and the head model and I have multiple sub-folders (one for each EEG data for each stimulation frequency that I used). See figure.

However, I would like to upload a different covariance matrix (that I already calculated in Matlab) for each sub-folder. To afterwards compute the sources for each sub-folder. Is this possible? Can I upload a different covariance matrix for each sub-folder?

I recommend you do not use any shared channel file.
Right-click on Group analysis > Edit subject, and select Default channel file: NO.

Then import again all your recordings.
With one channel file per folder, you'll be able to compute one noise covariance per folder as well.

Note that you are not expected to import recordings in this Group analysis subject.
Prefer the creation of a subject with a different name.

Thank you for your help.
I will do so.