removing entries from a sizer?

Hi list,

I don't know if am doing this the wrong way; any help is appreciated:

On my panel I have one "master" sizer (VertSizerPage_1) to which two
main sizers are added; the upper sizer doesn't change, but the lower
sizer changes according to the number of divisions required by the
user. If the user enters "5" then, 5 subsizers are added to the lower
sizer, which is then added to the "master" sizer, which is then used
to size the entire panel. The problem is that if the user changes 5 to
4, then 4 subsizers are added and I end up with 9 subsizers (4 plus
the previous 5). This is caused by the fact that I'm adding the
subsizers to the "master" sizer, but I don't know how to "delete" or
append one or more subsizers to the "master" seizer:

self.VertSizerPage_1.Add(UpperSizer,0,wx.ALIGN_LEFT|wx.ALL,5)
self.VertSizerPage_1.Add(self.LowerSizer,0,wx.ALIGN_LEFT|wx.ALL,5)
self.PanelGrid.SetSizer(self.VertSizerPage_1)

Thanks,
Jaime