Fund Replacement in MultiVendor Plan

We have a plan with 3 vendors, and there is going to be a fund replacement scheduled for only one of the vendors. How does the Plan go about providing a 30-day notice? Does the notice need to go to all active and terminated participants, no matter who the vendor? I'm assuming most recordkeepers won't distribute notices on behalf of another. Does the Plan need to handle the distribution themselves?
 

With no observation about what relevant law might provide:

If the plan’s administrator considers furnishing a notice to less than all participants and other directing persons:

Before the change date, is the to-be-replaced fund available to participants who have not yet invested in it, including those who do not yet use anything with the vendor that uses the to-be-replaced fund?

After the change date, is the new fund available to participants who do not yet use anything with the vendor that uses the to-be-replaced fund?

The fund that is being replaced is only available at 1 of the 3 vendors. In theory it can be available to anyone in the plan, if they were to switch vendors. Otherwise it's not available to them with the vendor they're with. Do they still need a fund change notice? Would it suffice to only distribute the notice to the participants at the vendor where the fund is being replaced, and then maybe posting the notice for everyone to see on the employers benefits page?