Hi!
Here's how I would tackle it, it sounds like you're pretty close:
I'd attach a separate FSM to each bomb. Bomb 1's FSM would react to the bomb being picked up, probably the same way you have it now. At the end of the timer/explosion sequence, I would add another state to the FSM that sets an integer value (say, "bombnumber" for example) to the next value, which would be 2. (you could also use the "add" function, and add 1, instead of setting it directly to 2. Your preference!)
On bomb 2, add a new FSM identical to the FSM on bomb 1, but add a new start state. Check the value of int "bombnumber" - if it does equal 2, then continue with the FSM for timer/explosion etc. Again, at the end of this FSM, add a a state which sets "bombnumber" to 3, or add one again.
Rinse and repeat for all the bombs you want picked up in order!