Not sure if you mean "interrupt" as the ususal tecnical term in programming.
Interrupt means stop execution of the current code regardless of what this code is doing right now
run down the code of the interrupt-service-routine then go on with whatever the code was interrupted at.
ISR usually are used if you need a reaction in less than 0,1 milliseconds.
Now starting your bell doesn't have to be accurate down to 0,0001 seconds.
Post your code to show what your code is actually doing.
If your main-loop needs more than 0,1 secnds to run through completely the interrupt won't help much.
In every case it does not help if you are using a display or some other additional hardware.
Trying to use an interrupt for something that takes more time than 10 milliseconds is the badest idea of all.
If your loop needs more than 0,1 seconds to run through completely this can only be by using the function delay()
Then it is about time to switch over from blocking timing based on function delay()
to NON-blocking timing based oon function millis()
I'm speculation. Post your code so that the forum-users can analyse what your code is doing
best regards Stefan