dual site landing page

[jasonhar]

Situation: I have a website on plchardware.com.au. I want to have a new (prestashop) site for the same company on a subdomain of that (new.plchardware.com.au)but want to keep the old one for SEO and for die-hard users.

I’m wanting to have a landing page from plchardware.com.au: with two options, one that goes to to the new website and the other to the old/current website.

Question:

Is there a way to land on a landing page other than the index.php (I don't want to change the current index.php) or how would I best go about this? perhaps a js popup?

also, is there any potential problems I may encounter in trying to do this?

Just need some advice.

Thanks

[shacker]

you can add a index.html

this have priority to index.php