An alternative is to try to book for 4 people.
If you are able to, it means there are at least 4 empty suites or 2 other passengers have already booked. There would be some chance of adjoining suites because if the other 2 passengers are a couple, they would have taken adjoining suites leaving the other one available for you. But if they are not, then it is possible they are seated across the aisle leaving no adjoining suite available.

If you are unable to book for 4 but fewer, the chances of an adjoining suite would be much much poorer.