Simply prepare the stock, and reuse the developer until exhausted. Ilford recommends reusing it for up to 10 films. If you decide to use it one-shot, simply discard after use.

Can you reuse Ilford multigrade developer?

It has good keeping properties, so can typically be reused, and is available as 500ml, 1L and 5L items. It is used at a 1+9 dilution with 1L bottle producing approximately 700 resin coated 10x8" prints or 450 fibre base 10x8" prints. ... A 1L bottle at a 1+9 dilution will enable 100 10x8" sheets of film to be processed.

Can you reuse developer?

Yes, as long as the developer isn't one shot. The bottle/packaging should make reuse clear.