If I am understanding this correctly and all of the identities are from the same authoritative source and have the same identity profile and you are trying to use different attributes based off certain conditions, it sounds like you would need a complex manager correlation rule to accomplish this.
If you end up needing a complex rule, SailPoint Services can assist in writing this rule based off your requirements. Even if you do write this rule yourself, you will still need to submit it to SailPoint for review since it is a cloud executed rule. Information on this process can be found here.