we have 3 external web urls which will come on our frontend f5 and redirect to internal web urls and use as a revers proxy

no no no Kevin all request will not contain one of these three host names. I just asked about the else rule that is this correct or not might be I am wrong. the hostname is defined, which will redirect to whom like below.

https://site1Ex.com --> http://site1in.com https://site2Ex.com --> http://site2in.com https://site3Ex.com --> http://site3in.com

request should be like above. and all external web URLs (https://site1ex.com .....) will use a common Virtual server.

and all internal web urls having below IP address site1in.com-> 10.10.10.1, site2in.com ->10.10.10.2, site3in.com ->10.10.10.3

then where we will assign these ip address ? so external traffic will goto internal web urls. how it will deside? is need pool member or not?