Generally, your dojo's bank/financial institution should be able to help you with that. In most cases, once you get your dojo's bank to agree, you have to get your members to fill out and sign an authorization for automatic withdrawal to get the process established.
I'm wondering if we even have a formal financial structure as I think about it. Probably do but I'll have to find out what it is.
A better question on my part might have been, what sort of results have you all experienced with the concept?