Is it possible to return parent document with optional child?

Hi guys!
I have company as a parent document and its relation status with other company (a child document with parent id as companyId):
company: {companyId, name, address, ...}
relation: {myCompanyId, otherCompanyId, status}
I am goint to find companies by some conditions and using has_child statement (to specify myCompanyId). But I don't want to the result depends on existing child documents. In other words I'd like something like LEFT OUTER JOIN in SQL.
Or a suitable solution is to return parent documents with no full childs but with childs which match some conditions
Is it possible?

Hi einfoman,
Can you provide your query (json encode formate ) for better solution.