Indeed, a default feature I doubt, but to event it would be possible. That's what EGM is all about. If you can think it, you can make with a little effort put in to it :p
It would be as simple as creating an event to activate the system. Then a conditional branch to check to see if Item A is found in your inventory and if item B is found in your inventory. If so, then remove those two items, and add the new combined item.
Of course... you can make it much more complex than this.
Oh, and lets not forget about the menu maker which can take care of the visuals, to add that sleek and sexy finish to it! ^-^
