"Summon Allies" usable for commanders?

[Saulot]

Zamaza said:
Well, can you make a spell specific to a pretender? I can do nation, but not specific units...

Amos is correct... Though I present three alternatives:

Only for your pretender:
The closest approximation would probably to have it require paths or a significant pathlevel you're unlikely to get from national mages. N8 spell or something.

Only for a type of unit:
An alternative is to require a mage/priest combo, of which there would be only the one mage/priest that you can recruit. If you have N3H3 commanders, then only those could cast the spell. The spell would then have a path/holypath requirement. Non-national Mage Priests tend to be rare, and keep in mind that a mage could be made into a prophet to be able to be included.

Only for your prophet:
If you want only one unit to be able to do it, anything requiring let's say, N4H4 would mean only one guy, turned prophet would be doing it.