As @trpnhntr said adjusting the plan around your outdoor rides is probably your best strategy. This is easily done in Sweet Spot Base as the rides are very similar and you’ll likely have the fitness to complete any of the rides.
For Build and Speciality this can get trickier. The rides can be varied and ramp up from week to week. For reference, I asked a similar question during General Build: Replace VO2 or Threshold workout with outdoor ride. I’m in the second week and it’s going well. When my Weds hammerfest gets rained out or weekend time constraints mess with my long rides I always have a backup. I’m happy with the compromise in results…since I don’t race it’s ALL about the group ride for me.