Priority for resouces

Firstly, i wanna thank Projeqtor did hep me to manage our team very good.

I have a concern and need your help.

Example:
i have two activity A (priority is 1), B (priority is 2).
A will be assigned resource S1 (8hours) and S2(8hours)
B will be assigned resource S1 (8hours) and S2(8hours)
But, S2 will start his job only when S1 done.
It mean each activity A/B will have duration 2 days instead of 1 day.
Total duration of this plan is 3 days instead of 2 days.

How can i setup this plan with projeqtor?

Thanks.