I looked up the family in the census (below) to help me picture where they are - in Røjkjær in Vind sogn, Ulfborg herred, Ringkøbing amt.
The church in Vind sogn (Vind parish) was apparently built in 1200 and is pictured here:
http://sepper.dk/vind/More photos:
http://www.vindkirke.dk/Fotogalleri.aspxMore about the church history:
http://www.vindkirke.dk/Kirkens%20historie.aspxGoogle translate can help if needed.
Maybe you're familiar with this map posted at ddd.dda.dk, showing the amts of Denmark:
http://www.dis-danmark.dk/kort/kort.htmAnd a map showing the herreds within Ringkøbing amt:
http://www.dis-danmark.dk/kort/kortring.htmAnd an email address for the priest at Vind is posted on the home page of the above website.
Parishes used to serve a civil as well as religious function. Births, marriages, deaths, were recorded in the churchbook etc. Danish government is reorganized and so I suppose perhaps it could be said the parish does not exist in the way it did in the time of Simon Iversen.
Of course the area encompassed within the parish is still there.
Is this answering your question? I'm no expert and maybe you were looking for a more technical answer re. church governance or civil governance?
1787 Danish Census
Ringkøbing, Ulfborg, Vind, Rogkier, , 4.Familie, FT-1787
Simon Iversen 56 Gift Mand Husmand og Tækker
Mette Jacobsdatter 49 Gift Hans Kone
Iver Simonsen 10 Ugift Deres Søn
Maren Iversdatter 61 Enke Mandens Søster Faar Almisse
Gregers Pedersen 2 Ugift Hendes Datters Søn, avlet udenfor Ægteskab
Jochum Jensen 54 Gift Mand Inderste og faar Almisse
Johanne Nielsdatter 60 Gift Kone
1801 Danish Census
Ringkøbing, Ulfborg, Vind, Røjkjær, , 14, FT-1801
Simon Iversen 69 Gift Huusbonde Huusmand med jord
Anne Njelsdatter 43 Gift Hans kone
Maren Iversdatter 75 Enke, Opholdende, Nyder almisse af sognet [identified as Simon's sister on 1787 census]
It's unlikely any graves from this era for your family remain at Vind Kirkegård. In Denmark graves are typically reused after a period of some decades.