Triple-boot BSD grub problem with loading FreeBSD

[Mr-Biscuit]

The machine in question isn't ready as of yet to be connected to the internet.
NetBSD has FreeBSD as (/mnt) in /etc/fstab and the filesystem type as ffs.
Both OpenBSD and NetBSD can boot from the NetBSD grub menu.

Using unhide $FREEBSD, root (hd0,0,a) isn't enough.
The kernel /$KERNEL?PATH causes the system to hang.
I'm thinking that either NetBSD grub cannot differentiate between UFS2 and FFS or that using grub on OpenBSD would provide better results.

When I am able to correct a few problems, I will post the files that are/will be requested. Currently, this is a general question.

I reinstalled FreeBSD and used the FreeBSD boot manager as the default.

[Mr-Biscuit]

To install Net, Open, and FreeBSD to a machine do the following.
Install FreeBSD and create partitions for Open and Net. All values are in the 160 to 169 range for file types.
Do a basic install of FreeBSD.
Install OpenBSD and make it the default. Use the OpenBSD FFS made by the FreeBSD install.
Install NetBSD and the NetBSD bootloader on the resrveed FFS area.
Go back and reinstall FreeBSD on the UFS2 created earlier.

From here, you can use the FreeBSD bootloader, grub, or grub2.