[CentOS] Access host from host

HI,

I don't know if this is the right place to ask but here is what I am
looking for.

I have a centos 5.3 server in DMZ . All of the access to and fro is
blocked. I have someother  servers in my network which they can access
to my server at DMZ. Now to connect to the server "directly" at DMZ
(ssh, rdp. ftp), is it possible to allow access via the accessible
another servers?

Thanks
Paras.