Effect of URL change on Website

[teconsite.com]

Hello we are developers and we have just created a new webpage for a client of us.

The problem is that we can not replace the old one by the new one, cause our client has developed over 15 satellite pages that calls directly to the code of the old page. If we completly remove the old page we will make those 15 pages go down. Those pages are working over domains specially register for SEO reasons.

For example

Main page is www.euroair.es

Satellite page is www.aireacondicionadodaikin.com

Satellite page has pretty good ranking for search term "aire acondicionado daikin"

As I told you, we have a new page but we can not make the page work over root domain. So we thought we could make it work over www.euroair.es/es, and make a redirection 301 of homepage and another important inner pages.

We chose "/es" folder because it seems like a language folder, but we are not very sure of the effects of pages working on that folder instead of working on root directory.

What do you think? Is this matter important or doesn't?

Thanks

[LabadieAuto]

I have had good results by using the rel="canonical" tag on the satellite pages.  If you have access to the satellite pages then copy the content onto the new domain.  Place the canonical tag pointing to the page on the new domain.  I have also found that this will give the new domain a huge boost in initial rankings.