Can ARC use be restricted so that some processes don't use it?

This is with respect to system backups via NetBackup in our case.

I'm making an assumption that when a full system backup is taken all the data read from disk and sent over the network goes through (populates?) the ARC, which seems likely to me.

From this I'm assuming that with weekly full backups that are larger than the system memory then the ARC is flushed out, losing the weeks built up usage from user apps?

If the above is correct, is it possible to tell Solaris (10 & 11) not to use the ARC for NBU?

Sorry if this is answered elsewhere, I've searched here and Google but got nothing back