diff --git a/pdal/Options.cpp b/pdal/Options.cpp
index 62b6a70841..f344528c8d 100644
--- a/pdal/Options.cpp
+++ b/pdal/Options.cpp
@@ -99,10 +99,21 @@ void Options::addConditional(const Option& option)
 }
 
 
-void Options::addConditional(const Options& options)
+void Options::addConditional(const Options& other)
 {
-    for (auto& o : options.m_options)
-        addConditional(o.second);
+    for (auto oi = other.m_options.begin(); oi != other.m_options.end();)
+    {
+        const std::string& name = oi->first;
+        if (m_options.find(name) == m_options.end())
+        {
+            do
+            {
+                m_options.insert(*oi++);
+            } while (oi != other.m_options.end() && name == oi->first);
+        }
+        else
+            oi++;
+    }
 }