Initplan placed at the righttree or the lefttree of joinnode

Hi,

I try to make some special query plan like the following.
I have tried a lot SQL, but failed.
Can Initplan placed at the righttree or the lefttree of joinnode?

          (Fake) QUERY PLAN
-------------------------------------------------------------------
 Hash Join  (cost=13.15..26.48 rows=140 width=8)
   Hash Cond: (test1.a = test.a)
   ->  Seq Scan on test1  (cost=0.00..11.40 rows=140 width=4)
   ->  Hash  (cost=11.40..11.40 rows=140 width=8)
        ->  InitPlan 1 (returns $0,$1)
Or

         (Fake)  QUERY PLAN
-------------------------------------------------------------------
 Hash Join  (cost=13.15..26.48 rows=140 width=8)
   Hash Cond: (test1.a = test.a)
   ->  Seq Scan on test1  (cost=0.00..11.40 rows=140 width=4)
        ->  InitPlan 1 (returns $0,$1)
   ->  Hash  (cost=11.40..11.40 rows=140 width=8)

Best regards