Hi SilverApe,
You probably want to think about and plan for the different things which may need to be addressed because it can affect how you approach the whole problem to begin with.
In this case you may want to have several options.
(a) target a single 'locked on' target and keep locked on until the target is destroyed, or the missile hits something else by accident, or runs out of thrust/fuel
(b) target the 'target' which is nearest and not yet destroyed, keep going until its hit ot runs out of fuel / thrust.
(c) you could set up an array of objects you can consider targets and index through them
I haven't ahd time to look at targeting a gameobject yet, but will do today.
IPete2.