[TYPO3-mvc] Other direction in relation between 1:N

[Lars Peipmann [Infield Design]]

Hi there,

I have created a new Extension with several Models with the Extbase 
Extension Builder. ModelA has a 1:n Relationshop to ModelB. It is easy 
to get all ObjectBs from ObjectA, but how can I get the ObjectA of ObjectB?

I can not find anything in the code of ModelB. Is there a default 
function or do I have to implement a function for this?

Best,
Lars