Right now sos handles sos magics and send the rest of the cell content to subkernels. There is however a slight chance that a subkernel defines the same magic as SoS, so

%get
blah

will cause some problem if %get is supposed to be sent to the subkernel.

I suspect that we can add some syntax to separate sos magics and subkernel magics, something like

%get var --from R
%
%get

Not that we have a similar problem with # and ! so in case the subkernel actually handles # or !, we should perhaps do something like

%
! something for subkernel

The separator could be %, %stop, or %--, or two blank lines...