Yes!  It's very possible that you could take all three exams in one sitting.
The PVVET will issue one exam at a time. When you are finished with the examination, please inform the VE that you would like to take another test. The examiner will usually make an offer to take the next element.
If you've failed an exam, it may be possible to re-take the exam depending on the venue and allotted time. You will be issued a different version of the examination.