eerie movie about a deranged young woman and her crimes

Hi folks,
I remember having watched a movie on (German) TV some 15 years ago which I would like to identify. these are some elements of the plot which I remember:
a) Background /setting
The story was supposed to take place in a very rural part of the U.S.; I think it was a small community of, maybe, some hundreds of people; or even smaller in terms of population; lots of woodlands in that area (in other words it wasn't set in the great Plains, nor in the South West). The small community was under the influence of one single family who owned a great part of the land, and further this family owned much of the local business and industry; you can see that the family is more feared than respected (especially the grandfather of the female main character must have been not only a wealthy person but also a very threatening "strange old man"...).
There were two daughters in that family; both got along with each other fairly well (at least until something happened, see below!). One of them left the village, at some point, with the intention to go to a big city. From then on, nothing ever was heard of her, and it seems no one of the village people did much care about her whereabouts. And further, when some time later the other sister also left, it was basically the same...
What I do not remember is whether the mother was still alive or already deceased like the father.
b) The crisis that lead to the crimes
From several "flashbacks" we get to know what was behind it all: One sister fell in love with a young guy from the same village; they went to the same college (?) and everything seemed to go well - but then the young man left her and - chose to leave the village, together with THE OTHER SISTER! At that point his former girlfriend must have gone mad:
--- Caution, here follows a big spoiler! ---
c) The gruesome truth behind the facade
Pretty late in the movie it turns out that the deceived / humiliated young woman took terrible revenge on those who had done this to her - somehow she must have managed to talk both of them into returning back to the village; then she killed them, and in some cellar (?) she arranged a terrible scenery:
I remember there was a long table covered with white linen, it was decorated with all sorts of expensive and beautiful china, silver forks and knives etc., there were lots of candles; on the plates there were rotting remains of various food - and around the table there sat three (or more) people, all in a mumified state!! I remember one female wearing a bride's gown. That was obviously the sister who supposedly had left for the big city - either she had been lurked back or her sister had killed her of before she could do so, i.e. she "had always been there"... I think the other one indeed murmurs something like that, staring at her sister's "mummy", with a crazy "smile"...
The scene might have been filmed not in the basement of an average house; maybe it was a place where to store wine barrels (or, in old days, ice) - in any case there must have been the "right conditions" to allow human corpses not to rot away but to turn into "mummies". You know, there's a kind of cellar which lies only halfway below the ground and has it's entrance not through the house (if there is any) but rather through a massive (single- or double-winged) wooden door behind which there leads a steep stairway downwards.
Indeed a very special kind of a wedding celebration!! Very eerie...
Unfortionately this is all I remember - neither do I know the title of the movie nor can I tell how the story ended.
Please, who knows the title?
I'm not sure about this - but somehow I feel the movie title contained something like the words "lake" and "secret" or "mystery".
d) Date and country of production
I'm 99% sure it was made in the U.S. (1 % goes for Canada, but I don't think so) - and it must be older than 20 years. Very probably the movie dates back to the 1980s or early 1990s.
Kind regards
Andreas (123all4me)