Multiple email addresses - any alternative to ask everyone to sign all my keys?

[Philipp Klaus Krause]

Hmm, since everyone seems to think "He doesn't consider the unviersity
computer secure enough for something, so he shouldn't consider it secure
enough for anything", it seems I'm failing and communicating what I want
to do. Maybe having a look at the following scenario will help:

I have three computers, a smartphone named CONFIDENTIAL, a desktop in my
office named SECRET, and one in the underground shelter with armed
guards and the dog that needs to be fed the right type of meat to let me
through named TOPSECRET.
I have email addresses confidential at me, secret at me and topsecret at me.
People sending confidential mail will send to confidential at me, and
expect a reply within a short timeframe, so I need to be able to decrpyt
and read the mail on CONFIDENTIAL. On SECRET, I want to read mail sent
to confidential at me and secret at me. People that value security over timely
processing will send mail to topsecret at me. On TOPSECRET I want to be
able to decrypt mail sent to confidential at me, secret at me and opsecret at me.
Nothing that happens to computer CONFIDENTAIL may allow other people to
read mail sent to  secret at me or topsecret at me. Nothing that happens to
SECRET may allow other people to read mail sent totopsecret at me.

I can handle this scenario by having three keypairs, one for each of the
email addresses. But this would require everyone to sign all three of
these keys. Is there a way to handle this secnario, such that people
only have to sign one key?

Philipp