Transition priorities?


How can we define transition priorities in UML state charts??

suppose if i have a state S1 and a condition connector, i draw two transitions T1 and T2 to condition connector from state S1. These transitions have same contions, so now which transition will fire first?

I need to give priority to these transitions, please help me how to do this?

Thanks and Regards,

How to give priorities to transitions if there are two transitions???