When you have two leagues that play the same night/share common locations but don't have the same reserved dates it is best to generate the schedule together but specify the different reserved dates.
Video: How to add different reserve dates for two leagues
Go to Menu > Manage > Schedules/Charts > Surface Scheduler.
Click on Generate schedule
1. Options
Recurring dates. (Add the furthest dates you need for the one league that needs longer then the other)
3. Choose a round-robin/league and reserve the dates you need.
Note: It's quicker to be in the ALL, to add the common dates that need to be reserved. They will apply to both. Then select the round-robin to add the extra/specific dates you want to add to one league only.
Do the same for the other.