How to creat a initialize block

I want to creat a initialize block to initialize some parameters. Now, I creat a block whick will creat a variable as the flag to show this model is initialized,and any block need the initialization will check this flag. However if there is another mdl include one block whick need the initialization but there is no initialization block acutually, the block will still perform as the initialization block existing because the flag aready created by other mdl.