Yes, you can be preselected for more than one profile and/or function group, but in most cases a candidate can only be tested for one profile in one function group per testing period. Therefore you will be invited to sit the tests for these different profiles/function groups in the same order as the requests were sent to EPSO by the recruiting services.
However, the same candidate can be invited to competency tests for different profiles during the same testing period. This can happen when the candidate has already passed previously the reasoning tests.
Neither the recruiter nor the candidates or EPSO can influence the order of test requests being processed. This is due to the fact that the rules of the Call for expression of interest clearly stipulate that success in one (earlier) test can influence the situation of the candidate by making further testing redundant, while a failure may result in blocking the possibility to be invited to test for 6 months.