This worked for me. I could pass through same realtek wifi usb adapters.
<hostdev mode='subsystem' type='usb' managed='yes'>
<source>
<address bus='3' device='10'/>
</source>
<alias name='hostdev0'/>
<address type='usb' bus='0' port='2'/>
</hostdev>
<hostdev mode='subsystem' type='usb' managed='yes'>
<source>
<address bus='3' device='9'/>
</source>
<alias name='hostdev1'/>
<address type='usb' bus='0' port='3'/>
</hostdev>