Alternative phrase/term for 'middle men'

Solution 1:

The most literal synonym is go-between. A better and more formal-sounding term would be intermediary.

Solution 2:

Intermediaries might be the word you're looking for.

Solution 3:

An existing answer suggests go-between or intermediary and I up-voted that because I'd lean towards intermediary myself. However, I would also suggest:

• liaison

I have a few more, with similar meanings but different connotations, for others who might ask the same question with different goals:

• agent
• representative
• front line or first line of defense
• buffer (somewhat condescending, but accurate)
• envoy