extending the SHA-2 addon for the Shib IdP

[Tom Scavo]

Regarding the shib extension for SHA-2:

https://wiki.shibboleth.net/confluence/x/H4O3

How difficult would it be to extend this addon so that the IdP could,
say, configure SHA-256 by default, but then have the ability to
override that default on a per-RP basis (for those SPs not compatible
with SHA-2)?

I'm not asking anyone to do anything, I'm just trying to understand
what's possible.

Thanks,

Tom