Approving a record which is having N - N relationship

Hello All

I'm having a requirement where 2 entities having N to N relation and for approving entity A ,entity B must be approved by user B

1) Entity A(owner:  administrator) 2) Entity B(owner: Financial officer)

Relation : N to N

i) "Administrator" creates an Entity A record and adds Entity B records and submit for the approval

ii) "Manger" will qualify this agreement. and it will qualify only if Entity B records are approved by financial officer.

iii) so how could we make this Entity B approved for only Entity A record1. because Entity B record may have association with another Entity A record.
i thought create 1 check box field approved or not . but this one works  for 1-N relationship only.  

Any help will be appreciated. Thank You.