Thanks for Your answers!
Well it seems combination printing is indeed what i'm trying to make use of. I'm not familiar in all those names though.. I have one enlarger, three negatives, i want to mix them into one print. Thats the idea. To make it all clear - lets say i have an image of a person standing (gray background) and a landscape. I want to put the person into the landscape. I cannot apply sandwich here because of misproportion. Perspective is ok though. The problem was that i could not mask it all so precise to avoid halo around the person. Third neg contains sky elements and i can handle with this one with sandwitch so no problem here.
As to my printing experience, i'm not the master, but i'm not a newbie too I'm printing for something like 6 years now, but never ever tried nothing so complicated. Im afraid the biggest challenge here is the moment of switching negs. I have only one carrier I dont really need another enlarger so i'm trying to work it out with what i got only.
What i'm looking for are some tips and tricks, ideas that will make it all work. Something like Bill Burk ( thanks!) suggested