my high school doesn’t have my sport

this is a long story:

i attended one high school until the end of my sophomore year but had to transfer to a new high school for my junior year. i’m a senior now and my current high school has a marching band that had its first year the same year of my transfer so i participated because i came from a high school with a big marching band that i was an active part of. my old high school also runs this program in the winter called indoor percussion. if anyone by any chance is familiar with what this is maybe you might have some insight. well i was part of this too but my current high school doesn’t have that so i missed out last year. if any of you have any kids that play sports its really not a small deal. it’s like telling a lifelong athlete he or she can’t play anymore. it’s been devastating to say the least and so, basically, i’ve been missing this so badly that i asked the instructors of my old high school to see if the administration would let me in. after all, i used to go there. but they won’t because of so-called liability issues. i’m 18 now so should that be a factor? and i have heard from multiple people that there is a “rule” that exists that if your high school doesn’t offer a program, you’re allowed to participate in a nearby school that does. does this only refer to clubs and not sports?? that wouldn’t make any sense to me because that excludes a much bigger population of students that play sports than do clubs. is it a state thing? a school thing? i’ve been looking on the internet for an answer but my situation is a little too specific to do that. please if anyone has any experience, if you’ve gone through or know someone who has gone through something similar and has had a better outcome than i did, could you tell me how? i understand that no matter what it comes down to whether or not i get permission, and obviously i haven’t, but i feel like it shouldn’t have ended that easily. maybe i’m wrong but i just need some advice. should i be dissatisfied? would you keep on it if you were me? please.