How to have multiple classes share pointers to a common class

I'm trying to determine the right approach to a design issue, but I am struggling to find something 'right'.

In simple terms:

• I have multiple functional classes that each need to interact with multiple common classes. (all created on the heap with New)

Eg

A class [a] object needs to be able to call methods in class [x], [y] & [z] objects
A class [b] object needs to be able to call methods in class [x], [y] & [z] objects
A class [c] object needs to be able to call methods in class [x], [y] & [z] objects

I have 3 solutions so far:

1. Make the common classes (x, y, z) global objects (or a singletons) so the functional classes (a, b, c) can just call the objects directly. However, I dislike the idea of making things global.


2. Pass pointers to the common classes (x, y, z) to each of the functional classes (a, b, c) during initialisation for later use. However, if a common class is deleted, the functional classes have stale pointers.


3. Have a single global object (perhaps a singleton) that 'manages' the common classes (x, y, z), and the functional classes (a, b, c) request a common class pointer as/when needed from this global object. This allows them to know if the pointer is NULL immediately.

Previously, I've used (2), but over time I've become unhappy with this approach.

I think I'm currently favouring (3) but still uncomfortable with having a global object/singleton.

I've been searching around for a design pattern that fits this kind of scenario, but can't find anything that fits, maybe due to not knowing the right keywords.

Is there a common design approach/pattern to this problem?