Problem with redirect

Hi,
My name is Edwin and I’m new here to this forum.
I’m a bit in trouble.
I have created a website and on a subdomain of this website I have a webshop.
example. www.rental.shop.nl is the shop and shop.nl is the website.
On my shop.nl website I have an iframe pointing to the rental.shop.nl
So far so good but google is indexing the rental.shop.nl and this is just the shop without further information.
I want to redirect visitors of rental.shop.nl to shop.nl
I ran in troubles with redirect becuase the iframe to the created an endless loop between the subdomain and the domain.
I thought that htaccess might help me but Iám not able to find the right script.
I would like to setup a redirect with an exclusion for the shops ip address. Is tehre anybody who could help with this one?
Thanks

Hmm… page not found think i am getting

Hi, that’s correct because as mentioned these domains are just xamples. the real shop is still offline.

ofc - .htaccess may help - if you want to redirect one domain to other domain

add it to rental.shop.nl .htaccess file

Redirect 301 / http://your-site

and remove iframe from the main site.

Thanks for your fast responces.
I will be more precise.
the shop is running on a subdomain because we want to create more websites using the same shop. for example rentalamsterdam.nl, rentalutrecht.nl etc. For this reason the shop is on a subdomain because we want to use the same shop for all city’s.
Customers should go to the domain of their city. Customers from amsterdam go to rentalamsterdam.nl rental amsterdam has an iframe that shows the subdomain with the shop.
We want to avoid that visitors enter the shop directly because this is just a naked shop without any contact details.
I tried htaccess with a redirect which works fine but ofcourse the domain rentalamsterdam.nl must access the shop.
I hope to find a way to redirect everyone except my own mainwebsite.
I made a redirect with an exclusion of the IP adress of the shop but it does not work most likely due to a lack of htaccess experience. hope you can help. thanks edwin