diff --git a/src/main/resources/etc/xsd/MIMformat/v2/1.2/MIMFORMAT_Mim.xsd b/src/main/resources/etc/xsd/MIMformat/v2/1.2/MIMFORMAT_Mim.xsd
index 271a581c..606c7580 100644
--- a/src/main/resources/etc/xsd/MIMformat/v2/1.2/MIMFORMAT_Mim.xsd
+++ b/src/main/resources/etc/xsd/MIMformat/v2/1.2/MIMFORMAT_Mim.xsd
@@ -327,7 +327,8 @@
       <xs:element name="gegevensgroeptype">
         <xs:complexType>
           <xs:sequence>
-            <xs:element ref="mim-ref:GegevensgroeptypeRef"/>
+            <xs:element ref="mim-ref:GegevensgroeptypeRef" minOccurs="0"/>
+            <xs:element ref="mim-ext:ConstructieRef" minOccurs="0"/>
           </xs:sequence>
         </xs:complexType>
       </xs:element>
diff --git a/src/main/resources/input/IHW/props/IHW.xlsx b/src/main/resources/input/IHW/props/IHW.xlsx
index 2dbddf93..3d6137dd 100644
Binary files a/src/main/resources/input/IHW/props/IHW.xlsx and b/src/main/resources/input/IHW/props/IHW.xlsx differ
diff --git a/src/main/resources/xsl/Validator/Imvert2validation.xsl b/src/main/resources/xsl/Validator/Imvert2validation.xsl
index 9ae7df22..af56ed18 100644
--- a/src/main/resources/xsl/Validator/Imvert2validation.xsl
+++ b/src/main/resources/xsl/Validator/Imvert2validation.xsl
@@ -879,7 +879,7 @@
         <xsl:next-match/>
     </xsl:template>
     
-    <xsl:template match="imvert:attribute[../../imvert:stereotype/@id = ('stereotype-name-objecttype')]">
+    <xsl:template match="imvert:attribute[../../imvert:stereotype/@id = ('stereotype-name-objecttype','stereotype-name-composite')]" priority="1">
         <!--setup-->
         <xsl:variable name="class" select="../.."/>
         <xsl:variable name="defining-class" select="if (imvert:type-id) then imf:get-construct-by-id(imvert:type-id) else ()"/>
@@ -894,6 +894,13 @@
             imvert:stereotype/@id = 'stereotype-name-attributegroup' and not($defining-class/imvert:designation = 'class'), 
             '[1] type must be an UML class', imf:string-group(imf:get-config-stereotypes('stereotype-name-attributegroup'),' or '))"/>
         
+        <xsl:sequence select="imf:report-error(., 
+            imvert:stereotype/@id = 'stereotype-name-attributegroup' and not($defining-class/imvert:stereotype/@id = ('stereotype-name-attribute','stereotype-name-composite','stereotype-name-interface')), 
+            '[1] type is not allowed here: [2]', (
+                imf:string-group(imf:get-config-stereotypes('stereotype-name-attributegroup'),' or '),
+                imf:get-config-stereotypes($defining-class/imvert:stereotype/@id)
+            ))"/>
+        
         <!-- Is het attribuut goed gestereotypeerd? -->
         <!--TODO alle relaties tussen construct van een bepaald stereotype valideren op basis van primary en context/parent info uit configuratiebestand. Dus als eerste aparte slag na canocalisatie. -->
         <xsl:variable name="allowed-primary-stereotype-ids" select="$configuration-metamodel-file/stereotypes/stereo[construct = 'attribute' and context/parent-stereo = 'stereotype-name-objecttype' and @primary = 'yes']/@id" as="xs:string*"/>
@@ -904,7 +911,7 @@
         <xsl:next-match/>
     </xsl:template>
     
-    <xsl:template match="imvert:attribute[../../imvert:stereotype/@id = ('stereotype-name-composite','stereotype-name-complextype')]">
+    <xsl:template match="imvert:attribute[../../imvert:stereotype/@id = ('stereotype-name-composite','stereotype-name-complextype')]" priority="2">
         <!--setup-->
         <xsl:variable name="class" select="../.."/>
         <xsl:variable name="defining-class" select="if (imvert:type-id) then imf:get-construct-by-id(imvert:type-id) else ()"/>