Hello Tproper,
There isn’t currently that functionality, however it is being discussed within the Defold team I believe (Any way to get the list of children of a game object? - #14 by britzl).
I will say, generally this isn’t something you should do, in my opinion, it will almost always result in highly-processing intense code, and can almost always be replaced by properly using the messaging system.
If you want to describe your situation I, or others, might be able to provide advice on a potential approach?
Cheers,
Spen