Use UIElements Foldout to organize the properties

[FoldoutGroup("Group2", ScopeType = GroupScopeType.ScopeBegin)]
public float Value3;
public float Value3_2;
[FoldoutGroup("Group2", ScopeType = GroupScopeType.ScopeEnd)]
public float Value5;

For more information, please refer to the "Grouping" description section