best way to merge two different quality meshes ?

[cyrilp]

Hi,

i'm working on a cathedral door project.

The aera of the door is very well defined and deserves a very high quality mesh.
The surrounding is not as well defined and i want to use only mediu quality mesh, i won't have many details but it will show how it looks.

is there an easy way to merge the high quality centered mesh with it's medium quality surrounding ? and what would be the best way ?