I did it using constraint actor. The setup was a bit weird by that was the only way to get it working. The truck had invisible physics box component attached to its root static mesh on a back using constraint component, similar box was attached in front of the carriage, connect to carriage root body with constraint component too. Inside of the truck blueprint, on event begin play, I spawn constraint actor and provide it references not of the actors but box components inside of truck and carriage actors. To get references to components I’ve used simple interface.
This way two actors will be connected together using those box components and you just need to turn constraint actor into a ball constraint. If connections is not too stable then just play with masses of components.
I think I still have all of this code inside of my Tracked Vehicles repository on GIT. The truck with connected carriage is a huge 8 wheeler car. Feel free to take a look at it.