Mixing H2 Zoom MS and XY files

Hello and thanks for your attention !
I’m getting oriented to my H2 and the Wavelab editor and I’m not sure I understand a fundamental concept.
On my H2 device, I created a 4ch “surround mode” recording of a band rehearsal. This setting, of course, created 2 Stereo files (i.e., an XY and MS recording).
On the H2, you can manually mix the 2 files in the “surround mixer” function for playback only (i.e., doesn’t retain the mix in a single stereo file).
Is there any way, in the WaveLab application, to mix the two stereo files into a single new stereo file ?