If the craft requires you to be there one on one then the child isn't old enough to apppreciate the craft.

Try dividing the group by age/ability and having the one group at the table for art while the other group has freeplay. Maybe even alternate days.

Have the whole group at the table with crayons and paper. Have 1-2 at a time doing the craft. Limit the amount of time per person. Yes they might be having fun but in fairness to the others they need to have less amount of fun but get to do it every couple days rather than too long all at once so that others miss out.