Solution Combination does not allow to define results values as output parameters. However, it does not mean that we cannot define these output values as parameters for a parametric study.
The idea would be using a Python Code object in the upstream simulation which forces Solution Combination to be evaluated and then take the value that user is interested in.
Here the code used in Python Code:
SolutionCombination = ExtAPI.DataModel.GetObjectsByType(DataModelObjectCategory.SolutionCombination)[0]
SolutionCombination.EvaluateAllResults()
StressValue = SolutionCombination.Children[0]
this.GetCustomPropertyByPath("Parameters Solution Combination/Maximum SEQV").Value = StressValue.Maximum.Value
(Be aware that we need to activate an output parameter in Property Provider).