Code:
#include <acknex.h>
#include <default.c>

typedef struct BODY_STRUCT {
	
	int volume;
	int mass;
	
} BODY_STRUCT;

BODY_STRUCT* ptr_slot1 = {volume = 10; mass = 15;}
BODY_STRUCT* ptr_slot2 = {volume = 20; mass = 25;}

typedef struct GEOMETRY_STRUCT {
	
	var price;
	BODY_STRUCT* pointer1;
	BODY_STRUCT* pointer2;
} GEOMETRY_STRUCT;

GEOMETRY_STRUCT geometry1;


void main(){
	
	//Geometry_Struct Geometry1;
	geometry1.price = 99.95;
	geometry1.pointer1 = ptr_slot1;
	geometry1.pointer2 = ptr_slot2;
	
	wait(1);
	
	camera.z = 1000;
	
	if(geometry1.pointer1.volume == 10){
		camera.z = 20;
		beep();
	}
}
will work for you, sorry about changing the cases,
also i changed price to a var, as you'll want it to support decimals (99.95)
you only need

Code:
struct BODY_STRUCT* Pointer1;
if you were using the same struct within itself

hope this helps