sooooo...in case someone was wandering, the solution was pretty simple. Instead of forming a new part pf code for separate waves, I used the existing one but changed it so that the 2.nd value (name, order, <--that one, blueprint) represented a spawn point, and not an order. Then I simply created a new, 6.th spawn point (needs to be done in several places in the .script file), placed a couple of them in water, et voila! I can pick which units spawn at which set of spawn points. True, I lost the ability to order the units (between attackMove and move), this was mitigated by setting all units orders to attack/move by default (funny thing though, some units remained on move order, while long range units, most ships, all air and all longer range experimentals are attack/move. Just as I need them
The solution was, in the end, simple as I had hoped it would be. In case anyone will want to mess around with survival waves and needs clarification - give me a hauler (here or via FAF lobby chat - PM).
Check out my 2 maps: "Survival_Mayhem&BO_3d_v1" "Survival_Mayhem&BO_3d_RPG"
as well as my mod: "Survival Mayhem&BO balance"
-- let me know of any bugs or issues regarding those 3.