Website split in two => What about redirects ?

Hello,
one of my salesmen sold 2 sites to a real estate agency in my area. The two sites must target 2 different localities.
The problem is that the current agency already has a site that has good rankings on both cities ...
So, if I want to maintain the rankings, I have to make page-to-page 301 redirects, but this implies splitting the site and therefore, half of the pages of the current site will redirect to site A and the other half to site B.

I've never been confronted with this situation where a site is split in two. Do you think that redirects in this case can be harmful (or not be followed by Google) ?

This is really some special case,
Making a guess, I would say that each of these pages will pass the link juice coming from the external links pointing into them & simply playing a role of redirect pages, nothing more... just like link shorteners,
idk if this will do help passing some domain authority and how exactly google would treat this, it's a testing gamble

If you're not ready to take a gamble, you should consider building a PBN website with this domain and link to both of these websites,
that will be much safer and the results are more guaranteed

Why not just link to the sites instead of 301 redirect?