Buffer for Planning multiple projects - How to do the best way

Hi all,

does anyone have a good proposal how to insert time buffers between Projects.
Lets say we need more time in the first Project. This should be compensated by a buffer which was already planned in the beginning So the Project takes longer and the buffer is automatically descreased. Also the ressource which uses more time is used by this buffer.

As a result the follwing projects are not moved due to real work allocation, which takes more than expected.

My own idea is a separat activity for which the ressource is assigned for some time at the end of the project, and always if it needs more time than the assigned work, it books it on the buffer. But I think that may be not the best ways to do.

Any other suggestions?

Thanks.