diff --git a/src/core/unit.c b/src/core/unit.c
index be57bdbd1d..35f41531c4 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -4888,6 +4888,7 @@ int unit_require_mounts_for(Unit *u, const char *path, UnitDependencyMask mask)
 int unit_setup_exec_runtime(Unit *u) {
         _cleanup_(exec_shared_runtime_unrefp) ExecSharedRuntime *esr = NULL;
         _cleanup_(dynamic_creds_unrefp) DynamicCreds *dcreds = NULL;
+        _cleanup_set_free_ Set *units = NULL;
         ExecRuntime **rt;
         ExecContext *ec;
         size_t offset;
@@ -4905,8 +4906,12 @@ int unit_setup_exec_runtime(Unit *u) {
         ec = unit_get_exec_context(u);
         assert(ec);
 
+        r = unit_get_transitive_dependency_set(u, UNIT_ATOM_JOINS_NAMESPACE_OF, &units);
+        if (r < 0)
+                return r;
+
         /* Try to get it from somebody else */
-        UNIT_FOREACH_DEPENDENCY(other, u, UNIT_ATOM_JOINS_NAMESPACE_OF) {
+        SET_FOREACH(other, units) {
                 r = exec_shared_runtime_acquire(u->manager, NULL, other->id, false, &esr);
                 if (r < 0)
                         return r;
@@ -6111,6 +6116,33 @@ int unit_get_dependency_array(const Unit *u, UnitDependencyAtom atom, Unit ***re
         return (int) n;
 }
 
+int unit_get_transitive_dependency_set(Unit *u, UnitDependencyAtom atom, Set **ret) {
+        _cleanup_set_free_ Set *units = NULL, *queue = NULL;
+        Unit *other;
+        int r;
+
+        assert(u);
+        assert(ret);
+
+        /* Similar to unit_get_dependency_array(), but also search the same dependency in other units. */
+
+        do {
+                UNIT_FOREACH_DEPENDENCY(other, u, atom) {
+                        r = set_ensure_put(&units, NULL, other);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                continue;
+                        r = set_ensure_put(&queue, NULL, other);
+                        if (r < 0)
+                                return r;
+                }
+        } while ((u = set_steal_first(queue)));
+
+        *ret = TAKE_PTR(units);
+        return 0;
+}
+
 const ActivationDetailsVTable * const activation_details_vtable[_UNIT_TYPE_MAX] = {
         [UNIT_PATH] = &activation_details_path_vtable,
         [UNIT_TIMER] = &activation_details_timer_vtable,
diff --git a/src/core/unit.h b/src/core/unit.h
index 09af8915dc..f2d4fd6a4b 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -810,6 +810,7 @@ static inline const UnitVTable* UNIT_VTABLE(const Unit *u) {
 
 Unit* unit_has_dependency(const Unit *u, UnitDependencyAtom atom, Unit *other);
 int unit_get_dependency_array(const Unit *u, UnitDependencyAtom atom, Unit ***ret_array);
+int unit_get_transitive_dependency_set(Unit *u, UnitDependencyAtom atom, Set **ret);
 
 static inline Hashmap* unit_get_dependencies(Unit *u, UnitDependency d) {
         return hashmap_get(u->dependencies, UNIT_DEPENDENCY_TO_PTR(d));
diff --git a/test/testsuite-23.units/testsuite-23-joins-namespace-of-7.service b/test/testsuite-23.units/testsuite-23-joins-namespace-of-7.service
index 6c7bbdb097..60c083a3f4 100644
--- a/test/testsuite-23.units/testsuite-23-joins-namespace-of-7.service
+++ b/test/testsuite-23.units/testsuite-23-joins-namespace-of-7.service
@@ -6,6 +6,6 @@ JoinsNamespaceOf=testsuite-23-joins-namespace-of-8.service
 Type=oneshot
 MountAPIVFS=yes
 PrivateTmp=yes
-ExecStart=test ! -e /tmp/shared-private-file-x
+ExecStart=test -e /tmp/shared-private-file-x
 ExecStart=test ! -e /tmp/shared-private-file-y
 ExecStart=touch /tmp/hoge
diff --git a/test/testsuite-23.units/testsuite-23-joins-namespace-of-8.service b/test/testsuite-23.units/testsuite-23-joins-namespace-of-8.service
index 42053b99f8..dac1cea7bd 100644
--- a/test/testsuite-23.units/testsuite-23-joins-namespace-of-8.service
+++ b/test/testsuite-23.units/testsuite-23-joins-namespace-of-8.service
@@ -5,5 +5,5 @@ NotifyAccess=all
 MountAPIVFS=yes
 PrivateTmp=yes
 ExecStartPre=test -e /tmp/shared-private-file-x
-ExecStartPre=test ! -e /tmp/hoge
+ExecStartPre=test -e /tmp/hoge
 ExecStart=/bin/bash -c 'touch /tmp/shared-private-file-y && systemd-notify --ready && sleep infinity'
diff --git a/test/testsuite-23.units/testsuite-23-joins-namespace-of-9.service b/test/testsuite-23.units/testsuite-23-joins-namespace-of-9.service
index a50a7fcdc2..6c64873b24 100644
--- a/test/testsuite-23.units/testsuite-23-joins-namespace-of-9.service
+++ b/test/testsuite-23.units/testsuite-23-joins-namespace-of-9.service
@@ -6,6 +6,6 @@ JoinsNamespaceOf=testsuite-23-joins-namespace-of-8.service
 Type=oneshot
 MountAPIVFS=yes
 PrivateTmp=yes
-ExecStart=test ! -e /tmp/shared-private-file-x
-ExecStart=test ! -e /tmp/shared-private-file-y
-ExecStart=test ! -e /tmp/hoge
+ExecStart=test -e /tmp/shared-private-file-x
+ExecStart=test -e /tmp/shared-private-file-y
+ExecStart=test -e /tmp/hoge