Toilets, Sinks, Showers, Tubs and Disposals - Shower tie-in to Toilet drain

Hi: I'm brand new to this forum and would appreciate any help.
I have a 7' x 3 1/2' ground level bathroom with a sink and a commode. I want to remove the sink cabinet, put in a mini sink, leave the commode, tile the whole room and install a shower, making the whole room a shower, my problem is how can I get a drain. Can I somehow tie into the toilet drain, or the sink drain. I have a main sewage line on the other side of the wall directly behind the sink. Please help.

How in the world are you going to get a shower, toilet and sink in a room only a fourth the size of a jail cell? The shower base itself will be a minimum of 30"x30", then the toilet and sink? I'd rethink the cramped quarter thing.

I too am adding a shower to a bathroom that only had a toilet and sink. We decided on a corner shower and it is a tight fit but it works. We extended the wall to give us a little more room. The whole room measures 5' X 10'. We aren't sure about how to tie in the shower drain to the toilet drain. If someone knows how to do that it would be helpful. Can we tie directly into the main sewer drain which is very close? We are on a septic system. Where can I find specifics on angles etc needed. And does it have to be vented like the sink is? I noticed that the date was 2005, so how did the project turn out??

you can tie in anywhere to a larger line where the drain is lower than the shower base/trap. Yes, the shower needs to be vented... and the shower drain needs to be a 2inch line. Your slope should be 1/4inch per linear foot.

Thanks, thezster, that really helps. We'll start that on Saturday, providing it warms up a bit here. ;)