Install kernel to specific triplet

So we already have the ability to change the compiler program name with the INI configuration variable PROGRAM_PREFIX like so:

[DEFAULT]
PROGRAM_PREFIX = ${ARCH}-gaisler-rtems${__RTEMS_MAJOR__}-

Which is nice because it will take care of cases where you’re building for multiple architectures at once (what I mean by that is cases where you have a single INI file with say a SPARC and a RISC-V BSP defined inside).
Unfortunately, once it’s time to install the newly built kernels, there is no way to set the install path in a similar way so it will copy the files to 7/riscv-rtems7 instead of 7/riscv-gaisler-rtems7
One could set the --destdir flag but, as far as I know, you cannot have it take variables like ${ARCH} so if you’re planning on install for two different architectures at once, this won’t work.

A workaround I found was to modify rtems/kernel/spec/build/cpukit/optinstall.yml to make it more similar to rtems/kernel/spec/build/cpukit/optprogramprefix.yml:

diff --git a/spec/build/cpukit/optinstall.yml b/spec/build/cpukit/optinstall.yml
index 22229f4063..fe4927f6d9 100644
--- a/spec/build/cpukit/optinstall.yml
+++ b/spec/build/cpukit/optinstall.yml
@@ -1,6 +1,6 @@
 SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
 actions:
-- set-value: ${PREFIX}/${ARCH}-rtems${__RTEMS_MAJOR__}/${BSP_NAME}
+- get-string: null
 - substitute: null
 - env-assign: BSP_PREFIX
 - set-value: ${BSP_PREFIX}/lib
@@ -12,9 +12,12 @@ actions:
 build-type: option
 copyrights:
 - Copyright (C) 2020 embedded brains GmbH & Co. KG
-default: []
+default:
+- enabled-by: true
+  value: ${PREFIX}/${ARCH}-rtems${__RTEMS_MAJOR__}/${BSP_NAME}
 description: ''
 enabled-by: true
+format: '{}'
 links: []
 name: INSTALL
 type: build

Then the INI file can define the INSTALL variable if needed:

[DEFAULT]
PROGRAM_PREFIX = ${ARCH}-gaisler-rtems${__RTEMS_MAJOR__}-
INSTALL = ${PREFIX}/${ARCH}-gaisler-rtems${__RTEMS_MAJOR__}/${BSP_NAME}

My question would be is there a better way to do this?