how install two freebsd9.2 on one disk?

[s m]

hello every one

for some reason, i want to install two freebsd9.2 OS on one SSD. is it
possible?? i have problem in partitioning my disk for two OS. you know
there is just one ada0 which can be partitioned.
if i define more partitions on ada0, can i use some of them for the first
OS and the others for second one? if yes, how can i manage booting?
how and where should i install boot manager in order to manage them in
booting time??

any comments or hints are appreciated
SAM