Whoa, that's a lot of Gouramis in a single tank. Not sure of the size of your tank but 3 males in any tank is asking for trouble in my opinion. Ah, just re read & your tank is very long at 5 feet. Still, I'd think any more than 2 males is very risky. Three Spot's are one of the most aggressive of the Gouramis, sometimes even the females, just saying................
If by "Blue Spotted females" you mean Opaline Gouramis, I'd try a couple more females first and then introduce a male when you have the time to monitor the situation long term. You can add Gold, Blue, Platinum or Lavender color morphs since they're really the same fish. Assuming that works out, add a couple more females, wait a bit & then add a second male or similar size to the other. At this point you'd have 2 males & 6 females. The safer bet would be to add a sort of dither fish like Rasboras, Cherry Barbs or Glass Catfish. Also very important, add a lot of plants to create different territories for each fish.
Good luck & keep us posted on your progress.