Sharing session across domain

[eluser]Unknown[/eluser]
Hi

Sorry if this topic had been posted before, but I had tried to find the similar topic but no succeed.

I had this case where I got 2 domain name register in server and I use 1 application.
Eg:
domainA = www.domainA.com
domainB = www.domainB.com

for domainA, i used default application

---application
---images
---system

for domainB, i create new folder named domainB

---application
---domainB
---application
---images
---system

By using htaccess, i rewrite rule whenever link is www.domainB.com, it will pointing to domainB folder. This case, it working fine.

The problem is, the session created in domainA are not same as domainB. This is problematic if we had to gather data from both domainA and domainB. Eg, let said, i add product A to add to cart in domainA, and another product B in domainB, i want to collect these both product and call it in shopping cart in domainA. Can i do that?

Need advise from expert and old guard how to implement these kind of problems? Normally doing shopping cart we have to use session right to keep the products in browser in certain amount of times. Are there any other methods beside this? I search in google mostly i heard something like this:

Assume you have a sites called www.innovativephp.com and www.innovativejs.com hosted on same server. Even though both sites are on same server, domain names are different hence you will see that the cookies will not be working in another top domain.

Thanks.