Cycle through GameObject Index

Hi Guys , i have a programming issue using GameObjects.  I need an ordered array of Targets 1-10.  The Ar camera will pick up a target and show the model for that target which i do fine , But if the sequence is out of sync like the person goes from image 1 to 4 it will show an error model becaise it isnt in order ,  So it must go 1-2-3-4  or 5-6-7-8 so on , .  So if 1 and next = 2 , show model if not  = 2 show error model untill  i find the image labelled 2 in the index.  It sound simple enough but i cant get it to work using Gameobjects as thry wont convert to ints to cycle though lists etc .  Its been weeks now and i cant figure it out.  Any help much appretiatesd. 

Thanks Darryl