C++ template: access members from source template struct

I want to create following class template:

Holds a list of objects of different classes, at compile time.
Being alled to do some computation on all members from a function.
Has a member to access each object of the list individually.
List and members can be created at compilation, no need for dinamic lists.
User interface must be simple, since it will be used many times and by different programmers on the teams, with little c++ experience.
Use C++14 standard, gcc compiler.

Example of user code. This is what I want to keep as simple as possible:

//list of sensors with a member for each sensor
typedef struct {
    cOneSensor_f A4_temp1 = cOneSensor_f ("A4t1", 0x1234 /*, x, y, ... and some more configuration data*/);
    cOneSensor_i B4_speed = cOneSensor_i ("B4s0", 0x2001 /*, x, y, ... and some more configuration data*/);
}Sensor_list_4_s;

//put the list inside a class template to be able to control all of them as a whole,
//but also access each sensor individually
cSensorsList<Sensor_list_4_s> Sensor_list_4( 4 );

//get sensor values
void do_sensors_stuff()
{
    //all sensors as a whole
    Sensor_list_4.update();

    //access each sensor individually
    float A4t1 = Sensor_list_4.A4_temp1();
    int   B4s0 = Sensor_list_4.B4_speed();
}

Behind the scene It can be as complicated as needed. It could be somehting like this:

A base class for objects
Some derived classes for different objects variations (I can manage all derived classes from base)
Template class to hold the list of objects.

class cOneSensor {}
class cOneSensor_f: class cOneSensor {}
class cOneSensor_i: class cOneSensor {}

template <typename T>
class cSensorsList: public T
{
private:
    int bus_code;
    cOneSensor *sensors_array;
    int nSensors;

public:
    cSensorsList(int bus_code):bus_code(bus_code)
    {
        //---  here is what I don't know how to do: get sensor list from typename T
        nSensors = 0; //getSensorListSize_from_T(/* T */);
        sensors_array = 0;//getSensorListPointer_from_T<T>(/* T */);
        // ---
    }
    void update(void) {
        for (int i=0; i<nSensors; i++)
            sensors_array[i].update();
    }
};

With this code I get:

✅ Members on cSensorsList to access each object individually.
✅ Symple to user perspective.
✅ All objects in a class.

But I don’t know how to:

❌ Within the class cSensorsList, get the list of members of template struct, to loop through all objects in the list to so some actions: the getSensorListPointer_from_T() function.

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