1. Learn the Object that's present in the container first.
Learn the Container Object:
2. Select the same object that you have learned previously (i.e the object present in the container) to learn. Now the "Object Selection - Add to Repository" window will display the hierarchy of your objects. Select the Container Object and Click OK.
Change the Object Hierarchy:
3. Right click the first object that you have learned & select cut. Then Select the Container Object, right click and select paste.
Note: You might have to go and set the index value to none.
Here is what i mean. Consider your current hierarchy as below
A->B->D
Now what you want is it to be A->B->C->D where C is the container
So if you can manually add C as a FlexObject in OR and associate some properties to it. Then you can identify the container. After that you can cut and move D under C manually. This way you will create a object hierarchy as required
A->B->C->D
But the success of the same would depend on if you are identifying C correctly or not