BF games with friends starts spamming trash.

we play with 1000pop cap, but normally isnt a problem.

when i play me vs 3 friends we all boom usually and jump into post imp stage as a result. The problem is that they just spam halberdier + skirmisher and some onagers (the only gold unit they use because i used to punish with mass scorps vs trash and they learned the magic of siege) from the start to end, i just go for the trash wars when i have 6k gold on the bank.

What composition should i throw to punish very hard this behavior?