Conflicting Supplements that compete for Absorption

Did a few searches on the topic and haven't been able to come up with alot of good information on it yet. Does anyone have a good resource that lists which supplements and nutrients that compete for absorption?

I want to make sure that the stuff I'm taking isn't going to waste. Which vitamins, amino's, and minerals work well together, and which compete? Also, which ones are better to take on an empty stomach?

Here is my supplement regimen right now:

AM -- Multi, Vitamin C(2g), Penis Enlargement pills, EFA pills(2g), Isopure Whey (big amino profile)
PM -- Gaba(1g), Calcium pills (4g)

I know that iron and zinc compete, as do vanadium and chromium. Vitamins seem to facilitate absorption of other vitamins and minerals, while some minerals tend to compete with eachother. Balch and Balch write a good book that covers the subject, called Prescription for Nutritional Healing.