Unlikely to get such information publicly. Usually you will have to use your informal networks eg NIE coursemates. Otherwise you can also guess, based on which schools are frequently requesting FAJT in the various FAJT channels, but this method is not accurate.

My suggestion is for you to enter the portal on 18 June, look at available openings for your CS and desired appointment, and apply accordingly. Openings are filled on a rolling basis so the earlier you secure your interview, the better. Ideally you should also keep your RO in the loop, assuming you don't intend to burn bridges, so that your RO can also do the necessary contingency and deployment planning.

As others have shared previously - remember that OPE interviews are a two-way street. The other side is looking to see if you are a good fit with them, but you can also ask and find out more about the other side to decide if they are a good fit for you.