You can do this with custom JavaScript verification. This verification should work for Q2A:
if (SSI_GetValue('Q2A_r1_c1') <= [% Q1_r1_c1 %]) {
strErrorMessage = 'First Q2A error message here.';
}
else if (SSI_GetValue('Q2A_r2_c1') < [% Q1_r1_c1 / 24 %]) {
strErrorMessage = 'Second Q2A error message here.';
}