Programming :: Dynamically Loading Libraries In GNU?

This post isn't really asking for a tutorial, but rather asking for some ideas. I've come up with a few ideas, but they seem cumbersome and unnecessary, so I was wondering if someone with more experience than me could out. Also, my explanations suck, but I'll try to do my best. So say I have an executable called X. At some point during its execution, X loads and uses (using dlopen and dlsym) a library called Y. In Y, there a bunch of functions that call the function called, for example, void *special_malloc (size_t). These functions come from another linked library (linked during compilation) called Z. Problem is, special_malloc contains some static variables within its scope, and when those variables are reset midway through a program, an invalid free occurs (special_malloc uses garbage collection). Now, what I want to happen is that whenever lib Z calls special_malloc, it instead calls the special_malloc defined in the executable X, so that these static variables are retained. Keep in mind that I have control of the Z library, meaning I can edit the source to fit my needs.