Your suggestion on B2 to H4 transfer

[Pele]

I have a valid h1b visa till 2022 and planning to bring my 1.5 yrs old and wife on h4 visa. However, because of the new suspension imposed on h4 by Trump admissions, we cannot apply for h4 till dec2020.
so i am thinking to bring my family on B2 visa and file
I-539 to transfer the B2 to h4 visa.
please advise me.