Rogerch's suggestion is good, but maybe it's worth considering an interval that will not repeat every 12 months, such as 2.5 or 3.5 months. That way the recitals will hit different parts of the year/different holidays. The drawbacks would be that the schedule is not as memorable, and every now and then PT's recital would coincide with the PW recital. Here is what a 2.5-month recital schedule would look like:
2024: Aug 15, Nov 1 (Halloween)
2025: Jan 15, Apr 1 (April Fools), June 15, Sept 1, Nov 15
2026: Feb 1, Apr 15, July 1 (USA independence day), Sept 15, Dec 1
EDIT: a little flexibility with the schedule might be nice too--instead of Nov 1, October 31 would be better if lots of people are interested in submitting Halloween music, for example.