The geometrical and mathematical definition of surface curvature in CAESES is all the same with the general one.
Therefore surfaces created in CAESES also has the same property of curvature with that of other CAD.
If the issue were just to adjust the curvatures at a boundary between two neiboring surfaces, we could make it in CAESES.
As far as I am understood from your post, it seems that you are looking for a method of fairing series of surfaces maintaining same curvature values and their boundaries.
In that case, the issue is not a matter of two-surface-connection any more and we need to pay extra efforts to make a fairing system within CAESES.
Neverthless what you want to have is just two-surface-connection maintaining curvature at the boundary, please upload the surfaces that you want to connect.
Then I will try connecting them.