About Destroying Objects

I am new to unity can any one help me out on this problem .Like I want to destroy 4 to 5 objects on collision of one object.Without using tags because i want to instantiate explosion on the position were 4 to 5 objects are going to be destroyed

Thanks in Advance

You coud used sendmessage or(or both) sphere cast. When having all colliders in certain area you can destroy the ones you like. Or like i said sendmessage, you just call certain method in certain area, and gameobject with that method will run it.
For example: