Thanks for the hint, I will try that ... since the servers are running in a production environment I will first take the quick route and plug from SIG{ALRM} to SIG{USR1} and send a kill -s USR1 $pid from the outside to initiate touching the files. Then there is no collision between the two timers.
Another solution has been posted above. I will see which works better.
I already spotted the places to turn into POE sessions, but the transition will take a while and has to be tested before going into production.