Homebrew PCBs

Does anyone know if it’s possible to tell Eagle that standard holes  
for through-hole components aren’t automatically attached to both top  
and bottom layers?  That seems to be the assumption, and I ended up  
with an isolated ground plane on my first board.  I fixed that easily,  
but I’m finding that I need to pay careful attention when laying out  
the board to ensure that I will have connected the layers together at  
a given hole where necessary.  For example, it’s easy to solder the  
leg of an IC to both layers without a socket, but if you *are* using a  
socket, you can only solder to the bottom layer (if the socket’s on  
top).

Thanks,
Brian

--
Brian Lalor / blalor@...
     You snooze, you lose
     Well I have snost and lost