That's not possible as far as I know. There aren't any real “hooks” into Time Machine.
However, you can do something nearly as good: you can disable the automatic backups that Time Machine does and run it manually instead:
tmutil startbackup --block --auto
Note this bit from man tmutil
The --auto option provides a supported mechanism with which to
trigger "automatic-like" backups, similar to automatic backups
that are scheduled by the system. While this is not identical
to true system-scheduled backups, it provides custom schedulers
the ability to achieve some (but not all) behavior normally
exhibited when operating in automatic mode.
It is not clear to me what the difference is, but it's worth noting that one exists.