Non-member conversion, different types same members

I have two classes I cannot modify, both have exactly the same members:

class Pose1 {
    public:
    double x,y;
};
class Pose2 {
   public:
   double x,y;
};

One part of the code uses Pose1 the other one uses Pose2. Is there a way to implicit convert these into each other? Now I have to write all the time

Pose1 p1(0.5, 0.5);
Pose2 p2(p1.x,p2.y);

I know I can write a conversion function which just does that once. But I have a lot of different types with lots of arguments.

Is there any way I can do something like:

Pose2 p2  = static_cast<Pose2>(p1);

I cannot use member function because I cannot change this code.

Thank you!