[Paraview] Filter - choose from multiple input

[Jakub Benda]

Hello all,
 
I'd like to create a custom filter that accepts arbitrary number of input connections (using InputProperty with multiple_input="1") and fills a CompositeTreeDomain widget (or similar) with those objects, so that the user can select a subset of inputs to work with.
How can this be accomplished?
 
Thanks in advance
 
Jakub Benda