Macro inside a macro

Hello everyone,
I would like to nest macros. for example:

define service {
… snip …
_MY_NAME joe
_B _SERVICEMY_NAME
… sniip …
}

define command {
command_name my_custom_command
command_line /path/to/command!$$_SERVICEB$$ # notice the use of double $…
}

the point is I want $$_SERVICEB$$ to return the string “joe”.
this configuration does not work…
is it possible to do it? if so how can it be achieved?
I hope I am clear…
Thanks,
Fol