Car insurance for B&A school transportation?

Hi! I am new to the forum, but have been reading your helpful q's and responses as a guest for many years. I have been a member on Daycarebear for many years.
Recently, we added before and after school care to our services, but our car insurance company won't cover us (total of 310km used for school transportation per year, as the school is only 900m away).

Does anyone on this forum have car insurance that covers regularly scheduled (so not "occasional") transportation of children? We'd be driving two children.
Thank you so much!:):)