This is not very hard to accomplish. Put a
GFI outlet in the feed before it leaves the
house, they allow downstream connections.
If your home is relative new it has a GFI
for the outside plugs probably located in
the bathroom. This solution would cost
about $20 for a GFI plug, or use a GFI
breaker, cost about $30. I have plugs in
front, out back and by the lake connected
this way and they work just fine.
Gil