Crosslinking - How bad for PageRank is a few links on every page?

About how crosslinking can effect PageRank when the crosslinking is minimal

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Hi all,

I've been doing some reading up on crosslinking here but have a question specific to our own situation. We have around 20 small sites and 3 large sites. Around 10 of the small sites and 2 large sites are all on the same server. Every page on most of the sites has a couple of links to one of the large sites in the page footers.

How bad is this? Could it be hurting our PageRank, which is 5 or 6 for the large sites as well as some of the smaller ones?

BTW: The sites are related, so it could be useful for someone looking at one site to find out about one of the others. Our largest site has 312 incoming links and a PR of 5, and we thought maybe it should have a higher PR.

Thanks for any suggestions~