Old website merging a small part of new site

[weeks]

Is this going to work?
Old example123.com is well established, doing what it should. But, it's going to be part of a new, flashly website with aaaaaa.com. I have built a "homepage" for the old site inside the new site, with it being aaaaaa.com/example123 and the good ol' example123.com domain will forward to that page.

There will be very little info about example123.com on aaaaaa.com, except on that page on the new site for it, and it will have all of the old info, updated, that example123.com offered.

Will those googling example123's name find the page we want them to find, which in the new interior page?

Thanks.

[aristotle]

Do you plan to interlink the transferred page internally with some of the existing pages on the aaaaaa.com site?

[weeks]

Yes, I will be linking to some pages on the rest of the site on what is to be the old homepage. Good or bad thing?
(thanks for getting back!)

[aristotle]

Well i was thinking of interlinking in both directions. That would make it a fuller integration, and allow googlebot to reach the transferred page from other pages on the site.