1 Timothy 1:3, KJV
As I besought thee to abide still at Ephesus, when I went into Macedonia, that thou mightest charge some that they teach no other doctrine
Titus 1:5, KJV
For this cause left I thee in Crete, that thou shouldest set in order the things that are wanting, and ordain elders in every city, as I had appointed thee
These two verses seem to indicate a certain "hierarchy layer" between elders and apostles. Paul is clearly an apostle and he appoints Titus to ordain elders in every city of the island of Crete. On one hand, Titus was appointed by Paul, which means that Titus is in position of submission to Paul the Apostle. However, Titus has the power to ordain elders in cities of Crete, which means that those elders would be in position of submission to Titus. Thus, we have the following structure: elders -> Titus -> apostles.
I wonder how those Christian groups that deny any such hierarchy levels in their governance—for example, Congregationalists—explain these verses.