I know that it is possible to restrict (or extend) the memory usage of the entire WP site using:
Is it possible to do the same for only one plugin that the website uses ?
No and even if you could, if the plugin ran out of available memory then the entire page generation would stop due to the fatal error.
You're better off fixing the plugin itself to not use as much memory or to just further increase the total memory allocated to WordPress/PHP.
Generally spoken, no, it is not possible for a particular plugin only. The plugin runs in the whole wordpress PHP process (normally) and therefore it shares the memory limit setting with the rest.
You can however try to limit the memory before each time the plugin is called. That would be prior any hook of it (that's possible) and then in the beginning prior the inclusion (that's much harder to achieve).
The define of
If you do not fear to deal with system internals, you can however limit the memory for the whole process properly as well as if you like it experimental, you can give runkit a try and execute the plugins code therein - somehow.