Rogue Junkbox Macro - Help?

[Blurred]

I wanted to create a macro that upon left clicking would still cast my pick lock spell (and if I had a junkbox in my inventory it would automatically unlock the first one), then upon right clicking will loot the junkbox. I am having problems with it however. When I have more than 1 type of junkbox it gets hung. Can someone please point out a way for this macro to work and maybe even include other types of boxes. Thanks in advance.

#showtooltip
/cast Pick Lock
/use [button:2] Sturdy Locked Chest
/use Battered Junkbox
/use Sturdy Junkbox
/use Heavy Junkbox
/use Strong Junkbox
/use Worn Junkbox

[B]Blurred

[Tunga]

Pretty sure you can't intelligently target in this way.