diff --git a/atlas/migrations/0041_auto_20220421_1747.py b/atlas/migrations/0041_auto_20220421_1747.py
new file mode 100644
index 00000000..f377e3bf
--- /dev/null
+++ b/atlas/migrations/0041_auto_20220421_1747.py
@@ -0,0 +1,23 @@
+# Generated by Django 3.2.10 on 2022-04-21 16:47
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('generic', '0026_ciduser_generic_cid_cid_291418_idx'),
+        ('atlas', '0040_casecollection_group'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='casecollection',
+            name='group',
+        ),
+        migrations.AddField(
+            model_name='casecollection',
+            name='cid_user_groups',
+            field=models.ManyToManyField(blank=True, null=True, to='generic.CidUserGroup'),
+        ),
+    ]
diff --git a/atlas/models.py b/atlas/models.py
index 431d74b1..04fb0487 100644
--- a/atlas/models.py
+++ b/atlas/models.py
@@ -651,7 +651,7 @@ class CaseCollection(models.Model):
         CidUser, blank=True, related_name="casecollection_exams"
     )
 
-    group = models.ForeignKey(CidUserGroup, on_delete=models.SET_NULL, null=True, blank=True)
+    cid_user_groups = models.ManyToManyField(CidUserGroup, blank=True)
 
 
     archive = models.BooleanField(default=False)
diff --git a/rapids/migrations/0048_alter_exam_cid_user_groups.py b/rapids/migrations/0048_alter_exam_cid_user_groups.py
new file mode 100644
index 00000000..dadc5af6
--- /dev/null
+++ b/rapids/migrations/0048_alter_exam_cid_user_groups.py
@@ -0,0 +1,19 @@
+# Generated by Django 3.2.10 on 2022-04-21 16:47
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('generic', '0026_ciduser_generic_cid_cid_291418_idx'),
+        ('rapids', '0047_exam_cid_user_groups'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='exam',
+            name='cid_user_groups',
+            field=models.ManyToManyField(blank=True, null=True, to='generic.CidUserGroup'),
+        ),
+    ]
diff --git a/rapids/models.py b/rapids/models.py
index ca1871ca..a5e4655c 100644
--- a/rapids/models.py
+++ b/rapids/models.py
@@ -596,7 +596,7 @@ class Exam(ExamBase):
         CidUser, blank=True, related_name="rapid_exams"
     )
 
-    cid_user_groups = models.ManyToManyField(CidUserGroup)
+    cid_user_groups = models.ManyToManyField(CidUserGroup, blank=True)
 
     def get_normal_abnormal_breakdown(self):
         # Inefficient but more extendible