Do Insight object support reference placeholders for IN filters?

[Matt]

I have these objects

• Level1Obj
  • Name
• Level2Obj
  • Name
  • Level1Obj
• Level3Obj
  • Name
  • Level2Obj

ok, let say I have these records

• Ground
  • Car
    • Ford
    • Ferrari
  • Bike
    • Harley
• Air
  • Plane
    • Boeing

I can setup filtering like this, and it works.
New object type Test

• Level1Obj
• Level2Obj 
  • filter = objectType="Level1Obj" and object HAVING outBoundreferences(Name like ${"Level1Obj")
• Level3Obj
  • filter = objectType="Level2Obj" and object HAVING outBoundreferences(Name like ${"Level2Obj")

ok, pretty sure that will work, but I want to have multiple, so I tried this, which does not work.

• filter = objectType="Level1Obj" and object HAVING outBoundreferences(Name IN (${"Level1Obj"))

Just wondering if the should work and I'm doing it wrong, or nope, this will not work by design?