EEG BDF type data read extension requirment

Describe the new feature or enhancement

we have a special BDF EEG data recorded by Neuracle EEG device , a complete subject eeg data is placed into many subfolders,while the evt.bdf is in the mainfolder. we try use the mne.io.read_raw_bdf to import the data，it makes sense when all data were loaded once time, but it cant work all the time,especially,we want load a segment overlap two bdf file and then meet error when using raw.plot() or raw.filter(). Because there are special attr belong to rawbase. our code is attached following,please tell us some adivice for this issue, thank you .

Describe your proposed implementation

I hope that a new data read method can be added into mne io package ,because there are many students and researchers using this type data. It can provide great convinience for people who use. if necessery, i could and would like to contribute to this work with your help.

Describe possible alternatives

import_multi_bdf_files.txt

Here is my code, it just can read data but cant plot or filter

Additional context

No response

Start with the attached import_multi_bdf_files.txt example and the mne.io.read_raw_bdf entry point, then reproduce the failure when loading overlapping BDF segments and using raw.plot() or raw.filter(). The issue needs a defined supported loading behavior and acceptance tests for multi-folder Neuracle EEG data before implementation can be scoped.