Check if column is substring of another column

PostgreSQL 8.1 question:

I have two columns.
policyNumber contains a 12-13 varchar string
AllPolicyNumbersIncluded contains one or more 12-13 varchar strings (policy nums) separated by commas

I want to check if policyNumber is contained in AllPolicyNumbersIncluded.

In SQL Server the PATINDEX function returns the starting position of the first occurrence of a pattern in a specified expression, or zeros if the pattern is not found, on all valid text and character data types, so something like this works:

SELECT me.policyNumber, me.CompanyName, me.Address, PolicyPrint.AllPolicyNumbersIncluded
FROM PolicyPrint INNER JOIN PolicyDetails me
ON (PolicyPrint.cicPolicyNumber = PolicyDetails.policyNumber
OR PATINDEX('%' + me.policyNumber + '%',cicPrint.AllPolicyNumbersIncluded)> 0 )

Is there a way to do this in a single SQL statement in PostgreSQL 8.1?

Thanks,

Keaton