Idiomatic Solution for not cleaning buildTmp folder

Hello TeamCity team and TeamCity users,

In our pipeline we are using a custom binary in a build step. It is not written by us and we have to use that tool. This tool uses temp folder to cache some integrity checks to speed up next builds. When it is executed by TeamCity, it uses buildTmp folder of agent instead of system temp folder. Since TeamCity cleans this folder between each build, we cannot take advantage of speeding up. What is the idiomatic solution for this problem? If we changed related environment variable  to another folder for only this build configuration, would TeamCity also clear that temp folder?

Thank you