When doing a rough plumbing can you install all fixtures on the same stack or do you have to install the toilet on its own?

Most bathroom groups are roughed in like this.
Toilet connects to sewer main. The toilet wet vents through the lavatory vent. Lavatory connects to toilet drain and runs a vent off the top the stubout tee out the roof or revents back into a dry vent in the attic.. The shower connects to the lavatory drain and is wet vented by it. This is a normal rough in and is acceptable both by local and state codes but also The Standard Plumbing Code Book. So, the toilet connects to the stack and the rest of the fixtures connect to the toilet drain line. Regards, Tom

Yea, what tom said.
And... we used to use a rule, never flush a major by a minor. A toilet is a major. If the toilet flushes by a minor then you want to vent the minor. A minor that is vented is called a dry vent above the minor and a wet vent below the minor until it reaches a major.