The simple answer is just wrap an IF around it. 8 years should be 2922
days, and I hope I grabbed the proper formula from this discussion, I
haven't tested it completely:

=IF(TODAY()-C2<2922,"Not Eligible",TEXT((27393.75+B2+C2)/2,"mm/dd/
yyyy"))

But for all the "another eligible company" parts, it gets more
complex. You'd have to have that data somewhere in the worksheet to
reference. No doubt it can be done, if those other dates are there.
So...what do you have?