Update Data on One Worksheet Using a Calculation Involving Data from Another Worksheet

Does my title even make sense?

I'm an independent World of Warcraft add-on developer and the first step in creating my new add-on is to build the functionality of my add-on in Excel. For those of you unfamiliar with the game, a very small part of it is that players can "level up" their crafting trades to allow them to use raw materials to create more powerful or useful items. In the WoW crafting system, some raw materials are used in more than one crafting trade. For instance, blacksmiths and engineers both find uses for copper bars. My new add-on's purpose is to track the player's inventory of raw materials and let them know when they have enough in stock to level a particular profession. Drawing on the copper bar example above, blacksmithing might require 100 copper bars and engineering might require 120.

My Excel spreadsheet maintains a worksheet that serves as a database for the type and amount of raw materials on-hand. I have separate worksheets for each profession that shows how many of a particular material is required to level the profession. When the number of copper bars on-hand exceeds the minimum amount required for a particular profession, some conditional formatting alerts me to that fact.

Here is what I need but cannot figure out:

As soon as I have on-hand all the materials for a particular profession, I want a button on my profession's worksheet that, when clicked, deducts the amount needed of each item from the master inventory list. For example, I want a button on my blacksmithing worksheet that deducts 100 copper bars from my master inventory list, then deducts x amount of tin bars from my master inventory list, etc. etc.

I have a function that I would like to apply to a particular cell, but I can't figure out how to put the function on the button to achieve what I'm after:

=(IF(VLOOKUP(A240,Engineering!A:B,1,FALSE)=A240,B240-VLOOKUP(A240,Engineering!A:B,2,FALSE),B240))

Of course the "240" is just a placeholder in this formula and I really just want the formula to iterate over each record on a particular worksheet. I figured as soon as I got this to work for one cell, I could just drag the formula over all the cells.

So am I looking at some tricky VBA/macro work, or is this much simpler than I think it is?

Not sure about the bumping rules around here, so I'm going to risk it with one bump.