Manager Correlation Across Identity Profiles?

@colin_mckibben along similar lines for manager correlation. Is it possible to correlate a manager across identities? Ex:- user is coming from identity profile B but their manager’s identity is coming from identity profile A. We tried the simple manager correlation on the source of identity profile B to map “extensionAttribute15” with the identity attribute “uid” but it doesn’t work and manager is blank for the user.