Create a new list dynamically

[floatingshed]

I have a list of dicts. One of the values in the dict contains several words semi-colon separated which I would like to be the names of dynamically created lists. I can iterate over the master list and separate the required list names but cannot figure out how to create and name the lists. e.g.

dict1 contains a,b,c I need to create lists a b and c and copy dict1 into each.

dict2 contains a,c,g I need to append dict2 to lists a and c, and create list g then copy dict2 into it.

At the moment I achieve this by creating pickled items on disc, as creating named files dynamically is a breeze. But as the master list grows the process slows...a lot!

I'd appreciate a pointer or two, thanks.
This is the disc/pickle version:

def CreateDict():

    with open(music, "rb") as f:
        try:
            while True:
                disc_data = pickle.load(f)
        except EOFError:
            pass
            
    for i in disc_data:
        category = (i['categories']).split(';')
        for cat in category:
            cat_data=[]
            cat = cat.lstrip()
            if cat =="":cat = "No category"

            cat_dir = db_dir+cat+'.db'
            if not os.path.isfile(cat_dir):open(cat_dir, 'w').close()
            
            with open(cat_dir, "rb") as h:
                try:
                    while True:
                        cat_data = pickle.load(h)
                except EOFError:
                    pass

            cat_data.append(i)
            output1 = open((cat_dir), 'wb')
            pickle.dump(cat_data, output1)
            output1.close()