boost parent fields BlockJoinQuery

[michael solomon]

Hi,
I'm using in BlockJoin Parser Query for return the parent of the relevant
child i.e:
{!parent which="is_parent:true" score=max}(child_field:bla)

It's possible to boost the parent? something like:

{!parent which="is_parent:true" score=max}(child_field:bla)
parent_field:"bla bla"^10
Thanks,
Michael