Different ressources with different planning on the same task

Hi All,

I have a problem to plan multi-ressources on the same task but with different agenda.
To be clearer (for exemple) :
Ressource A will work from Monday to Friday
Ressource B will work on the same task but only Tuesday and Friday

Do I have to divide the task for :
Monday : ressource A
Tuesday : ressource A + B
Wednesday, Thursday : ressource A
Friday : ressource A + B

The problem is that it seems that if the sub-task are next to each other they stick.
Thank you to confirm (or not) this process.