Yes,you can practice for a few laps for the R&D objectives and then forward to Q1.However,if you want to have a couple of laps in all the practice sessions then you have to retire to the paddocks and then start it again.Btw I strongly suggest that you practice because a lot of times rain starts mid race and if you have already practiced in those conditions then you will have a fair idea of the breaking points and the understeer of the car involved with that setup. Btw which difficulty are you playing on?