[igraph] Filter the number of hops

[Nirmal Raman Kannaiyan]

Dear All,

I have a network generated based on PPI for a list of candidate genes with 
order = 2 (neighbourhood).

neighborhood(ppi.graph,order,which(V(ppi.graph)$name %in% genes))

 What I really would like is to filter this network such that, I include nodes 
that have 1 or 2 hops between my Candidate Gene List and not include all the 
neighbours.

Any suggestions on how to arrive at this minimal network with only two hops to 
connect my candidate gene list.

Thanks and regards,
Nirmal