Matrix manipulation or operation help

i have two matrices like this

Now I want my matrix C to look like this below. The following is result of :items which are in B but not in A. my 99999 dishcode stands for 'All'. So 'OliveGarden 99999' means all the dishcode for OliveGarden are in A hence are gone from my resultant matrix C. What operations should i do to get this done?

[Neesha]

[] means there is a dataset , in my case it is number of dishes by qtr