Crystal Reports Multiple selection report

Message

     I have a report with 8 parameters from 3 tables.
I'm creating a searchable purchase order report.
I'm trying to create a report with multiple parameters selection options.

A date parameter sorts record between 2 dates. 
Then I have additional parameters for: 
closed/open status
PO Number
Po requestor
product name
Part number
Part type
Vendor

The idea of the report is to allow the user to select a date range to search, then be able to select one or more of the other parameter options to search and return the specif purchase order results.

For example:
Date range =  1/1/2014 to 6/1/2014
All purchase by requester Joe from vendor ABC with part type= laptop

I have the report working correctly with the date range and any one other parameter. But as soon as I add the third or more parameter selection to narrow down the results I get all sorts of bogus results.

I've tried all sort of combinations but this is my first attempt at multiple item searching. So far this is what I have:
IF {PURCHASE.PODATE} = {?PO Date range}
Then
{?Vendor} IN {PURCHASE.VENDOR} 
XOR
{?Purchase Order Number} IN {PURCHASE.PONUM}
XOR
{?Part Type} In {POITEM.TYPE}
XOR
{?Prioduct Name} IN {POITEM.PRODUCT}
XOR
{?PO Requestor} IN {PURCHASE.RESPONS}
OR
{?Part Number} IN {POITEM.PART_NUM}

I can get {PURCHASE.PODATE} and any other parameter to return valid. But if I try selecting 
{PURCHASE.PODATE} and {POITEM.TYPE} and {PURCHASE.RESPONS}

This should retun a list of purchase orders between the specified date where a {PURCHASE.RESPONS} has ordered a specific {POITEM.TYPE}

Can someone suggest a way to make this type of search work?

Thanks