Topic: Stand-alone operation for F-UC?

Hallo,
This is my setup in stand)alone (Fireface UC): IN>2 condenser mikes on i.1 & i.2
OUT> SPDIF > SPDIF IN on my Marantz PMD661. So I get 2 good preamps and a good converter too.
I use Totalmix v0.932 on a Macbook Pro to configure this setup. It works :-) ... but I notice that the input gain for i.1 & i.2 works separately and it's hard to work in such a way. So I want to group these two input... but how to do it in Totalmix, that's my question.
I begin to use it, so be clear, please, if you answer... ;-). Thanks for thereply. daniel