Has your A surface got to be on the inside ? if not female split mould and internal bag would be my route

Thou it somewhat depends on how you plan to join your quarters ? (I would go for male an female step joins one of each on every part

If you have to have A surface on the inside I would say getting a part off in one would be difficult ? can you do each quarter in two goes ? lay up to the centre line of the circle+ 10mm, trim once cured then release if wet lay or cover with PTFE tape if pre preg then lay up the second half of the mould going over your 1st laminate 20mm so your 10mm past the centre line again

Once cured strip both parts (with only 10mm past the centre line parts will have enough flex to be demoulded) abrade your joggle and bond quarters together

Depending on cost/material there is always soluable wash out cores

Or if your doing wet lay mould your own foam cores in quarters or halfs in A+B foam ,lay up over them and then get a bit brutal on the A+B with a chisel once the laminate is cured