I just don't know enough about using multiple dictionary files to talk intelligently about them.
I use the Addict Spell Check library to manage all of the spelling stuff. You can read more about it's use of multiple dictionaries here:
http://www.addictive.../ed-dictionaries.htmSo the DICTIONARYDIR variable i just added to the ConfigDir.ini tells the spell checker to look in this directory for additional dictionaries. I think that means it should show them in the Spelling Options as "Additional Dictionaries" that are now available.
Now it may only make those available for read-access as additional dictionaries, and insist that the actually modifications be done in an exclusive dictionary file -- or it may let you then choose a dictionary in that directory to use as the one to add to, i'm just not sure. And I also don't know if it locks it during changes -- but I would not be surprised if it does not lock it, and if it will let you share it and modify it and only lock it during short periods of changes. But I don't know for sure.
I also don't know what other programs you might have that also use this dictionary format (while this library can READ the Microsoft Office dictionary, it will not modify it).
I will add support for specifying multiple ; separated directories with DICTIONARYDIR. But you will still have to go to spell options in CHS to enable the dictionaries you want to use i believe.