diff --git a/proposals/admin.py b/proposals/admin.py
index da03187..1f29561 100644
--- a/proposals/admin.py
+++ b/proposals/admin.py
@@ -1,34 +1,51 @@
 from django.contrib import admin
+from django.contrib.sites.shortcuts import get_current_site
 
 from proposals.models import Conference, Talk, Topic, Track, Event
+from planning.models import Room
 
 
-class TalkAdmin(admin.ModelAdmin):
-    # Disable add button in django admin has it is too dangerous
-    # (it is easy to obtain incoherent data due to site framework)
-    def has_add_permission(self, request):
-        return False
-    # Filter for 'on site' topics, tracks and events
+class SiteAdminMixin:
+    exclude = ('site',)
+
+    def get_queryset(self, request):
+        return super().get_queryset(request).filter(site=get_current_site(request))
+
+    def save_model(self, request, obj, form, change):
+        if not change:
+            obj.site = get_current_site(request)
+        super().save_model(request, obj, form, change)
+
+
+class TalkAdmin(SiteAdminMixin, admin.ModelAdmin):
     def get_form(self, request, obj=None, **kwargs):
         form = super(TalkAdmin, self).get_form(request, obj, **kwargs)
-        # in fact, obj should never be none as 'add' button is disabled
-        if obj:
-            form.base_fields['topics'].queryset = Topic.objects.filter(site=obj.site)
-            form.base_fields['track'].queryset = Track.objects.filter(site=obj.site)
-            form.base_fields['event'].queryset = Event.objects.filter(site=obj.site)
+        site = get_current_site(request)
+        form.base_fields['topics'].queryset = Topic.objects.filter(site=site)
+        form.base_fields['track'].queryset = Track.objects.filter(site=site)
+        form.base_fields['event'].queryset = Event.objects.filter(site=site)
+        form.base_fields['room'].queryset = Room.objects.filter(site=site)
         return form
 
 
-class TopicAdmin(admin.ModelAdmin):
-    # Filter for 'on site' tracks
+class TopicAdmin(SiteAdminMixin, admin.ModelAdmin):
     def get_form(self, request, obj=None, **kwargs):
         form = super().get_form(request, obj, **kwargs)
-        if obj:
-            form.base_fields['track'].queryset = Track.objects.filter(site=obj.site)
+        site = get_current_site(request)
+        form.base_fields['track'].queryset = Track.objects.filter(site=site)
         return form
 
+
+class TrackAdmin(SiteAdminMixin, admin.ModelAdmin):
+    pass
+
+
+class EventAdmin(SiteAdminMixin, admin.ModelAdmin):
+    pass
+
+
 admin.site.register(Conference)
 admin.site.register(Topic, TopicAdmin)
-admin.site.register(Track)
+admin.site.register(Track, TrackAdmin)
 admin.site.register(Talk, TalkAdmin)
-admin.site.register(Event)
+admin.site.register(Event, EventAdmin)