Is it possible / desirable to have multiple RStudio.Rproj projects in the same Git repository?

In the past, I've always had RStudio project and Git repo at the same level (i.e. one repo per project). However, especially when collaborating with software engineers, it is advisable to avoid wildly spreading the Git repository. Is it possible to create multiple RStudio projects in one repo? If so, are there any important reasons this is bad practice?