Athletes can register twice for the competition, once for the U20 category and once for the Senior category. They will then receive 2 Bib numbers. As a trick, you could give the 2nd registration a fictitious bib number by placing a 9 in front of it.
For example, if the athlete has bib number 54, give him 954 for his 2nd registration. You do not issue the 2nd number, so that the athlete does the entire competition with 1 bib number.
Another solution is to make all events available for the U20 and U18 categories.
This has been automatically translated into English