How to update a particular model in Django Haystack(Solr)

Question

I have 2 models that I want to store and index in Solr.

Foo and Moo.

Now for this I have created 2 cores Foo and Moo in Solr.

In settings file I have created 2 indexes for this.

HAYSTACK_CONNECTIONS = {
'default': {
    'ENGINE': 'haystack.backends.solr_backend.SolrEngine',
    'URL': 'http://127.0.0.1:8983/solr/Foo'
},
'Moo': {
    'ENGINE': 'haystack.backends.solr_backend.SolrEngine',
    'URL': 'http://127.0.0.1:8983/solr/Moo'
},

}

Now while updating or rebuilding index I want to update a core with only the particular model it holds. i.e.

python manage.py rebuild_index -model Foo -using default
python manage.py rebuild_index -model Moo -using Moo

Is there any way to do this ? Or are my concepts wrong ? Am very new to Solr and Hasytack and the documentation is not very clear about this. Please comment I will update the answer.