diff --git a/src/interface.ps1 b/src/interface.ps1
index 2a04c52..a21ad7e 100644
--- a/src/interface.ps1
+++ b/src/interface.ps1
@@ -159,7 +159,7 @@ function New-RequirementGroup {
   $Requirement `
   | % {
     $r = $_.psobject.Copy()
-    $r.Namespace = $Namespace, $r.Namespace -join $NamespaceDelimiter
+    $r.Namespace = ($Name, $r.Namespace | ? { $_ }) -join $NamespaceDelimiter
     $r
   }
 }
diff --git a/test/interface.tests.ps1 b/test/interface.tests.ps1
index 658d4a1..fcb576a 100644
--- a/test/interface.tests.ps1
+++ b/test/interface.tests.ps1
@@ -115,4 +115,20 @@ Describe "New-RequirementGroup" {
     New-RequirementGroup -Namespace $namespace -Requirement $requirements `
     | % { $_.Namespace | Should -BeLikeExactly "$namespace`:*" }
   }
+  It "Should not contain multiple colons in a row" {
+    $requirements = New-RequirementGroup "a" {
+      New-RequirementGroup "b" {
+        @{
+          Describe = "1"
+        }
+        @{
+          Describe = "2"
+        }
+      }
+      @{
+        Describe = "3"
+      }
+    }
+    $requirements -join "|" | Should -Be "a:b>1|a:b>2|a>3"
+  }
 }