Thank you for the guidance!  The Schedule B question is worded as:

"4. At the end of the tax year, did the corporation:

     a. Own directly 20% or more, or own, directly or indirectly, 50% or more of the total stock issued and outstanding of any foreign or domestic corporation? For rules of constructive ownership, see instructions. If "Yes," complete (i)through (v) below"

The S-Corp A and S-Corp B are sister companies that do not own each other's shares.  Can the attribution rule apply here, that they own 100% of each other indirectly through the individual shareholder?  I guess I am shaky on these concepts....thank you!!