I have some existing cables run in PVC conduit running an outside lighting circuit.

Is there any way to splice a Tee into the existing run so I can pull another cable through to run a new lighting circuit off to another part of the garden. I do not want to interfere with the existing circuit so can't cut into the existing wire. 

I was hoping I could cut out a small segment of conduit and then clamp a Tee fitting over the two loose ends, although from prior experience and from what I can see in the catalogues the Tee  does not split open completely i.e. cannot be clamped over the outside of the existing run like a DQC saddle does.