How to remove a childnode when there is a parent node with ID in Powershell

I have an xml file , I want to remove the existing child node from the xml where there are parent nodes with specific ID Using Powershell

<

Portal PortalID="IPE">
      <DBConnection>
</DBConnection>
          <Spicer>
            <Filetype SpicerViewer="true">.jpg</Filetype>
            <Filetype SpicerViewer="true">.gif</Filetype>

           <Banner>
            <Top>
             <Left>fdgsf_FileName</Left>
             <Center>gsdfg_Revision</Center>
             <Right>Date</Right>
            </Top>
           <Bottom>
             <Left>dfgsdf_FileName</Left>
             <Center>fgsfd_Revision</Center>
             <Right>Date</Right>
           </Bottom>
         </Banner>
      </Spicer>
</Portal>

I have to remove the Banner node completely based on the Portal ID , as I have multiple Portal Id's in my config file