Extrude trimmed surface along normals

Hello. I want to extrude a surface along normals. (I guess it’s a list of trimmed surfaces - see picture 01

Rhight now my surface is not exactly a surface but a bunch o triangles with holes (trimmed surfaces).
Surface is not planar and I want extrusion to be tappered where fragments of surface are angled towards themselves. Basically I want a resoult that gives the offset component (+filled sides). I exported the mesh to blender and extruded along normals - that’s what it should look like - see picture 02

Unfortunately offset doesn’t seem to work with trimmed surfaces - or I should say it works but it treats every triangle as separate object and moves them individually so they come apart. I thought about joining all trimmed surfaces into one big surface but I don’t know how to do that. When I use extrude component with separate direction vector for aech triangle its not giving the result I want because extruded edges don’t remain joined with adherent edges of other triangles but instead interconnect into each other. Is there a quick way to tackle it inside GH?

You can take a look at that

Big thanks. It resolved all my problems:)