youre right...individual safes for the different individual parts is the safest option so they cant get back out without you knowing.
Sorry this wont work either. As all glock parts take a safe cracking course before they leave the factory in Austria. FYI - to make matters worse any cross-platform firearm that can except glock parts of ANY KIND such as my Kel-Tec sub2000 carbine (see avatar) will if possible, aid in their glock comrades escape. I have found the only safe way to store a glock firearm is to place the parts in multiple safes, one inside of the multiple others; then have them launched into Geo-syncronis orbit by the European Space agency (they are the safest I'm told).
As I have said before all we need to do to defeat our enemies is to simply drop glocks and ammo in the middle of the night in their country's. Before sunrise of the the same day they would all be wiped out by these crafty, self loading, self pointing, levitating killer pistols.