client specific variable in nis/automount map not expanded

[Freddie C]

I've been trying to set up an entry in one of my nis maps to use the $HOST variable something like this:
/tmpmnt $HOST,server1:/mnt/mntpoint

The $HOST variable isn't working as the mntpoint dir would always mount from server1 instead of the client I'm accessing the dir from. I've ensured that the dir to mount exist on the client and is exported out as well as restarting the nis and nfs services but to no effect.

I tried doing it through the automount map of the client and it is still the same. Leaving just the $HOST entry would give a directory not found error when cd to it.

Does anyone have a clue as to why I can't get the client specific variables to expand? Is there something I did not configure to get this working?