[BioC] Filter over group averages

[Michael Imbeault]

Hello,

Is there a way to easily filter genes on the average signal over groups 
(according to phenoData?). Let's say that in phenoData of my eset object 
I have 'Time' and 'Status' variables, which have 3 values each. I have 3 
arrays for each of the (9) conditions.

What I want is to keep genes with an average value of at least 100 in at 
least one of the resulting 9 conditions. The genefilter package 
seemingly only include functions to filter genes ignoring groups - is 
there an easy way to do the same taking into account groups?

Thanks,
Michael