I'm not too sure of the exact meaning (I should probably ask my husband later about it) but I think that this phrase refers to solicitation done by consultants, "not soliciting consultants".
I apologize for typing in English, I must have been online for too long bcuz I'm having trouble with hangul font again. -_-;
Well, anyway, to back up my point, below is the definition of "of" I found in an English-English dictionary.
-Derived or coming from; originating at or from: customs of the South.
-Caused by; resulting from: a death of tuberculosis.
-Associated with or adhering to: people of your religion.
-Belonging or connected to: the rungs of a ladder.
-By: beloved of the family.