You will need to give more context on what you are trying to do.
However, using an example of XOG'ing out multiple portles using the provided portlets_read.xml as an example, the format is:
<PortletQuery>
<Filter name="code" criteria="OR">abc,xyz</Filter>
</PortletQuery>
Please review and see if this can be applied back to what you are attempting to undertake.
I have also undertaken 'SOAP' calls, but my previous attempts were to only return 1 record, or, all records.
1 record
<Query xmlns=""http://www.niku.com/xog/Query"">
<Code>queryID</Code>
<Filter>
<code>abc</code>
</Filter>
</Query>
All records
<Query xmlns=""http://www.niku.com/xog/Query"">
<Code>queryID</Code>
</Query>
If you don't find a solution, why don't you just run the '1 record' example above twice, and passing required 'id' in each call?