You could model this:
Create a custom select form. This form has a data view with the object your want to pass to your verification microflow and a data grid which allows multi-select with the objects you wish to connect.
Create a custom save button on the data grid which passes the selected object and the enclosing object, verify the input and set the selected objects as reference.
Create a custom microflow which passes the object you need to verify to your newly created select form.
Screenshot to clarify: http://imgur.com/PoWQ3