If I have an obligor past due on several obligations can I send one notice listing all obligations that are past due. Or, do I have to send 3 notices to the same person, one for each delinquent obligation?

What is a SOC HOC notice?

The SCRA HUD notice

12 USC 1701x(c)(5)
(A)Notification of availability of homeownership counseling
(i)Requirement
Except as provided in subparagraph (C), the creditor of a loan (or proposed creditor) shall provide notice under clause (ii) to (I) any eligible homeowner who fails to pay any amount by the date the amount is due under a home loan, and (II) any applicant for a mortgage described in paragraph (4).

Sort of up to you, but since this is usually an automated process and sent with standard past due notices, do you actually combine such notices. I have never heard of a process like that for past due loans.

FWIW I would be hesitant to combine them.

Loans 1, 2, 3 are brought current. Loan 1 goes 45 days past due, 2 & 3 remain current. Are you going to send the combined notice listing 2 &3 when 1 is the only one past due?

If this is a one time notice to cover the current situation then as Randy stated it is a business decision but I would not advise a combined notice as an ongoing procedure.