Both Donny Most an Erin Moran appeared on the love boat at the same time

Both Donny Most an Erin Moran appeared on the love boat at the same time
I think it was a practice for casting sometimes to get 2 from one show to guest on the Love Boat.

As I recall, there was an Episode Where Joyce DeWitt (Janet 3s Company) and Richard Kline (Larry 3s company) appeared together in that same episode, but not in the same story line.