Use load template expressions to create a condition. For example, you have a metadata source file that contains rows for table and column objects. The TYPE field of the metadata source file specifies the type of object for each row. You want to create a lineage association between the columns only. You create the following lineage association:

<lineageAssociation ruleName="linkRule" condition="TYPE='COLUMN'">
		<from>PARENT</from>
		<to>ELEMENT</to>
	</lineageAssociation>
	

When you run the custom XConnect, Metadata Manager retrieves only rows from the metadata source file where the type is a column.