dont bother to ask who will have 1a/1b with you.
for those who are going to have 1a or 1b
i will rather suggest you to save the time and study more as you are actually doing everything yourself during these two stages....
its ok if you want to study together but from my experiences most ppl asking to meet up to prepare their 1a or 1b.....disappear right after the interviews....
their hr ppl interview way so many candidates than you can imagine and if you are just try to pass the test with throwing all the info into your brain right before the interview....you will probably receive the decline email as soon as you leave the cx building...