One thing that you could do is to change the Windows Appearance property to NOT open front panel when called. You can then have your main VI (VI_B) open the panel for VI_A as before, but it will not start with the panel open. If you are creating an executable, go to the VI Settings tab page and click on the line with VI_A and then Edit Settings. Turn OFF the Remove Panel property. This should work for you (I've done similar already anyway).
Rob
