Shower to toilet drain

I'm thinking of installing a shower stall in my basement bathroom. I'd have to break the concrete floor to install the drain. My question is: can I tie in the shower drain to the existing toilet drain? If so i'm assuming that it would share the vent for the toilet.

drain

CAN you do it? Probably. SHOULD you do it? That depends on more factors than you have not addressed in your question. It may or may not be vented by the toilet, but the normal situation would not be. It depends on how the existing toilet piping is arranged.

thanks, i guess the drywall's comin down...