Periodic membership dues

Hi, there,

I am part of an association (we are about 300 people associated) and we are thinking of using Dolibarr.

Bimonthly we pass on the membership fee for bank direct debit.

I have been able to test the application and it seems that it is advisable to create members and create a " affiliation " (“afiliación” in spanish) for every fee paid.

My questions are:
Is it possible to do this process without having to do it member by member?
In our case, most of them have the same quota, but there are special cases where there are more or less of them.
I know that there is the possibility of entering custom fields. Would it be possible to define in each member what is the fee they pay through one of these fields?

Thank you…