Item Merge

Ok, i want to have it so if you have 2 certin items in ur inventory u can choose to merge them or not, tell me if this would b a good way of accomplishing this:

Ill make an item called like MERGE ITEMS, then when u use it it checks item types in inventory slots, then if 2 r mergable 2 for a better item, it will come up with a dialog that says would u like 2 merge like Boots And Gloves or something, then u can click yes or no,if u click yes it removes the two items and gives u a different 1 (merged 1) if u click no it does nothing, what do u think or is there a better way that would b more user friendly i could do this?

Also, can some1 tell me how 2 make units unselectable, i cant figure it out.

Two answers to questions, so looks like I get to do the #) again.

1) It would be nice if when you had to combinable items, they would sorta be shaded different so you could see. Of course this would mean pain because you would have to make different items for each item combinable. Then after they would click on one they would combine.

2) Just give the unit the locust ability, although I personally like the trigger way. Apparently there is some sort of status or something called ALOC which what locust does; giving a unit that makes it unselectable.

Thnx for the second 1, on the first 1 though i want players 2 b able 2 use the items sepratly, then if they want to they can combine items to form better ones.