Business rules in schema

Hi all,

Can I define a business rules in xml schema definition.

For example: Consider a sample xml definition

<employee>
    <name>xyz</name>
    <age>30</age>
    <maxServiceAllowed>28</maxServiceAllowed>
    <maxAge>58</maxAge>
</employee>

So based on this hypothetical information, I wanted to have validation rule in schema such away that
maxServiceAllowed =  maxAge - age

Can I acheive this in schema? Thanks for attention.

Regards,
Arvind