At the moment there are two couple devices
#1 Mutual inductors
#2 3 Mutual inductors.
For each you set the coupling coefficient.
A better solution would be to have a mutual component (like an equation block) where you specify the K and the two inductors it links
This way more elaborate magnetically coupled circuits can be realised, something like a 3phase phase shifting autotransformer (for a 12pulse rectifier) comes to mind