Drainpipe into Cast Iron Soil Pipe

[BazP]

The drain pipe from my conservatory runs along the ground to a grid.
Right next to the gutter outlet is a cast iron soil pipe can I "T" into it ?
If so I would need to drill/cut into the cast iron and fit an adapter of some kind.
Now I've typed this I don't think its feasible.

 

[seco services]

is your drain/sewer combined or are they seperate as in soil pipe go's to the drain and your gutters go to soak aways ?

 

[BazP]

They are combined.