At the moment I don't see a way to make that possible.
When you send troops to strengthen a farmer the mood will remain 60% till your troops actually are there. Because of this you will send out all your troops and many of them will reach the farmer when it's already back at 100%.
An other problem with this is that you will focus on one farmer. You 'll keep increasing it's strength and attack after that.
But when you attack all farmers you will probably get more resources.
If I understood you wrong or you have a nice idea on how to realise this feel free post your ideas.
//edit
Seems to be a small bug in 1.7.5. The stop button isn't working.
~Uthar
When you send troops to strengthen a farmer the mood will remain 60% till your troops actually are there. Because of this you will send out all your troops and many of them will reach the farmer when it's already back at 100%.
An other problem with this is that you will focus on one farmer. You 'll keep increasing it's strength and attack after that.
But when you attack all farmers you will probably get more resources.
If I understood you wrong or you have a nice idea on how to realise this feel free post your ideas.
//edit
Seems to be a small bug in 1.7.5. The stop button isn't working.
~Uthar