How to choose php version for aptitude full-upgrade?

Question

Debian

When you connect the deb.sury.org repository, several versions of php become available. If you run the aptitude full-upgrade command, you will be prompted to upgrade to the latest version in the repository, namely php8.0. I need to limit to php7.1 version. How can I do this so that when aptitude full-upgrade is updated no higher than php 7.1.
I know, you can selectively install the version you want and choose which one will be active, but in my case this is not an option, I would like to just upgrade through aptitude full-upgrade.