How to choose the RecombinationScheme in MG5's FastJet

Hi,

I want to modify the "RecombinationScheme" in MG5's fastjet, but there is no corresponding option available. I have noticed that this setting can be found in "fjcore.hh". How should I go about making this modification? Is it okay to directly modify the parameters in fjcore.hh?

In file MG5_aMC_v3_5_0/ PATH TO PROCESS /SubProcesses/fjcore.hh:973.
***********fjcore.hh***************
enum RecombinationScheme {
  E_scheme=0,
  pt_scheme=1,
  pt2_scheme=2,
  Et_scheme=3,
  Et2_scheme=4,
  BIpt_scheme=5,
  BIpt2_scheme=6,
  WTA_pt_scheme=7,
  WTA_modp_scheme=8,
  external_scheme = 99
};
class ClusterSequence;
class JetDefinition {
public:
  class Plugin;
  class Recombiner;
  JetDefinition(JetAlgorithm jet_algorithm_in,
                double R_in,
                RecombinationScheme recomb_scheme_in = E_scheme,
                Strategy strategy_in = Best) {
    *this = JetDefinition(jet_algorithm_in, R_in, strategy_in, recomb_scheme_in, 1);
  }
****************************

Look forward to your reply, thanks.
Meisen