No beveling, I need align it to outer edges. So, this mean automatic subdivision(needed iterations count depends from poly size, and probably nearest faces angle in between). For example make 5 pseudo quads from large tris group (2 in one layer) and move new edges around on calculated distance to reach more round surface of this entire area. Same way for smaller tris in group, this time split it i.e. on 2 parts and do the same. Smallest shape forming polys should not be touched. You know entire logic of this. Which modifier do I need?
Actually now realized how to. Cut out needed parts, and smooth with modifier as separate objects. BUT catmull-clark method still has noticeable weakness, it approximates this task, but does NOT works as external only tris. Actually it does pretty counter thing and not only cuts edges to inner side but even completely doesn't touch base edges as anchors. I don't need smoothed geometry to be smaller, at least it's minimal changing.