The problem with "strange" jetways, is they probably achieve that behavior by not having their insertion point matching the first node of the hierarchy.
The problem is, the only thing GSX can possibly know about a jetway right now, is the insertion point, so it doesn't have any other choice than to assume the first node of the hierarchy is located in the same position, which is the most common case for standard jetways, even if we got reports that some developers also didn't align the two, even in standard jetways, possibly to overcome the jetway not being recognized by the parking ( too distant, for example ).
Right now, there's just no solution, since information about the underlying hierarchy cannot be obtained in any way from the SDK but, it's one of the new features that will be added to the Navdata API update that will be out in SU12, due in March, which should hopefully result in GSX being able to recognize any kind of non-standard geometry.