diff --git a/runbot/models/batch.py b/runbot/models/batch.py
index bd6f496d..1469d9e0 100644
--- a/runbot/models/batch.py
+++ b/runbot/models/batch.py
@@ -366,7 +366,7 @@ class Batch(models.Model):
         version_id = self.bundle_id.version_id.id
         project_id = self.bundle_id.project_id.id
         trigger_customs = {}
-        for trigger_custom in self.bundle_id.trigger_custom_ids:
+        for trigger_custom in self.bundle_id.all_trigger_custom_ids:
             trigger_customs[trigger_custom.trigger_id] = trigger_custom
         for trigger in triggers:
             trigger_custom = trigger_customs.get(trigger, self.env['runbot.bundle.trigger.custom'])
@@ -427,7 +427,7 @@ class Batch(models.Model):
         bundle_repos = bundle.branch_ids.filtered('alive').mapped('remote_id.repo_id')
         success_trigger = self.slot_ids.filtered(lambda s: s.build_id.global_state in ('running', 'done') and s.build_id.global_result == "ok").trigger_id
         trigger_customs = {}
-        for trigger_custom in self.bundle_id.trigger_custom_ids:
+        for trigger_custom in self.bundle_id.all_trigger_custom_ids:
             trigger_customs[trigger_custom.trigger_id] = trigger_custom
         for slot in self.slot_ids:
             if slot.build_id:
diff --git a/runbot/models/bundle.py b/runbot/models/bundle.py
index ae097a0a..9cab8493 100644
--- a/runbot/models/bundle.py
+++ b/runbot/models/bundle.py
@@ -48,6 +48,7 @@ class Bundle(models.Model):
 
     # Custom parameters
     trigger_custom_ids = fields.One2many('runbot.bundle.trigger.custom', 'bundle_id')
+    all_trigger_custom_ids = fields.Many2many('runbot.bundle.trigger.custom', compute='_compute_all_trigger_custom_ids', recursive=True)
     host_id = fields.Many2one('runbot.host', compute="_compute_host_id", store=True)
     dockerfile_id = fields.Many2one('runbot.dockerfile', index=True, help="Use a custom Dockerfile")
     commit_limit = fields.Integer("Commit limit")
@@ -194,6 +195,17 @@ class Bundle(models.Model):
         for bundle_id, batch_id in self.env.cr.fetchall():
             self.browse(bundle_id).last_done_batch = self.env['runbot.batch'].browse(batch_id)
 
+    @api.depends('branch_ids.target_branch_name', 'branch_ids.is_pr')
+    def _compute_all_trigger_custom_ids(self):
+        for bundle in self:
+            pr_branches = bundle.branch_ids.filtered('is_pr')
+            targets = set(pr_branches.mapped('target_branch_name'))
+            if len(targets) != 1 or targets == {bundle.base_id.name} or bundle.trigger_custom_ids:
+                bundle.all_trigger_custom_ids = bundle.trigger_custom_ids
+            else:
+                parent_bundle = self.env['runbot.bundle'].search([('name', '=', targets.pop())])
+                bundle.all_trigger_custom_ids = parent_bundle.all_trigger_custom_ids
+
     def _url(self):
         self.ensure_one()
         return "/runbot/bundle/%s" % self.id
diff --git a/runbot/tests/test_build.py b/runbot/tests/test_build.py
index b55d89b7..467d7707 100644
--- a/runbot/tests/test_build.py
+++ b/runbot/tests/test_build.py
@@ -125,6 +125,28 @@ class TestBuildParams(RunbotCaseMinimalSetup):
         build_slot = bundle.last_batch.slot_ids.filtered(lambda rec: rec.trigger_id == self.trigger_server)
         self.assertEqual(build_slot.build_id.params_id.config_id, custom_config)
 
+        # Test custom trigger if targetting non base bundle
+        branch_b_name = 'master-test-something-other-thing'
+        self.push_commit(self.remote_server_dev, branch_b_name, 'Subject', sha='d0d0abab')
+        self.repo_server.project_id.process_delay = 10
+        self.repo_server._update_batches()
+        bundle_b = self.Bundle.search([('name', '=', branch_b_name), ('project_id', '=', self.project.id)])
+        bundle_b.write({
+            'branch_ids': [(0, 0, {
+                'name': '1',
+                'is_pr': True,
+                'pull_head_remote_id': self.remote_server.id,
+                'pull_head_name': f'remote:{branch_b_name}',
+                'target_branch_name': bundle.name,
+                'remote_id': self.remote_server.id,
+            })]
+        })
+        self.assertEqual(bundle.all_trigger_custom_ids, bundle_b.all_trigger_custom_ids)
+        self.repo_server.project_id.process_delay = 0
+        bundle_b.last_batch._process()
+        build_slot = bundle_b.last_batch.slot_ids.filtered(lambda rec: rec.trigger_id == self.trigger_server)
+        self.assertEqual(build_slot.build_id.params_id.config_id, custom_config)
+
     def test_trigger_dependency(self):
         self.start_patchers()
         self.additionnal_setup()