Multi-Selection Issues

I have created a Command that pulls in data from Oracle. It is just a SQL statement at you will see below. It contains 1 parameter andI would like this parameter to be multi-valued, but it is not working. Below is the query. I am tried to have the users put in values such as 1,2,3 and just using the built-in shuttle, but neither of them work. Having using put in a comma deleimted string such as 1,2,3 gives me an invalid number error. Any ideas on how I can pass a multi-valued selection to my query below? Thank you very much.

SELECT (lname||', '||fname||' '||mname) AS Name
,TO_CHAR(corp) AS CORP
,TO_CHAR(center) AS CENTER
,TO_CHAR(dob,'MM-DD') AS DOB
,ACCT_UNIT_LAWSON
FROM humrec2.emprofile
WHERE corp='10'
AND empstatus = '1'
AND year = TO_CHAR(sysdate,'yyyy')

AND (INSTR(','||{?ACCTUNIT}||',', ','||ACCT_UNIT_LAWSON||',') > 0)