Anish,
I don't think RFC 1422 directly address the topic you raised.
However, a reading of RFC 1424 provides an answer in the syntax and
processing description of the CRL-storage message. It allows multiple
CRLs, from different CAs, to be sent in a single message. Thus the CA
for Bellcore could bundle CRLs from its subordinate CAs and sent them
to the PCA. However, it would also be valid to have each subordinate
submit its CRL directly to the PCA. I would the part of the PCA
policy statement that deals with CRL management to state any other
conventions for CRL-submission for each PCA. In the absence of other
statements, it would seem OK to do either a bundled CRL submission
or per-CA submissions.
Steve