Idea to execute sessions in workflow at different timings

Would you give me any command or some idea to execute sessions in a workflow in different timings?

Let me explain you clearly,
I have 7 sessions in a workflow, some are simulateniously running...
My requirement is to run 3 sessions in the morning and 3 in the afternoon and 1 mid night (after completing the 6 sessions).

[b]Question asked by visitor N SRIRAM[/b]

we can go for scheduling the session or by using control m command by writing script.