Hopping into the business-to-business fray are two more online procurement exchanges, one to supply the hotel industry and the other for the specialty-metals marketplace.

As in other industries, the hotel venture marries fierce rivals,

Marriott International

(MAR) - Get Report

and privately held

Hyatt

in this case, while eight competing specialty-metals companies have united in the other.

Marriott, the No. 2 lodging company in the world behind

Starwood Hotels & Resorts

(HOT)

, and Hyatt aim to get a piece of the booming hotel-supply industry with their venture, which has yet to be named but will be formed later this year. Though the two companies plan to serve other hotel chains, in addition to restaurants and perhaps hospitals, they already account for about 10% of the $50 billion hotel-supply business in the U.S.

Competition for the hoteliers' exchange, to be based in the Washington, D.C. area, includes

Purchasepro.com

,

Hsupply.com

and

Zoho

.

Marriott, based in Bethesda, Md., and Hyatt, based in Chicago, have selected e-commerce service provider

GoCo-op

to power the site. The company is based near Orlando, Fla.

Merrill Lynch acted as Marriott's financial advisor.

Shares of Marriott closed Monday trading at 33, up 1, or 3%. (Marriott closed Tuesday trading up 1/4, or 0.8%, at 33 1/4.)

MetalSpectrum.com

, the metals exchange, has been developed to buy, sell and distribute aluminum, stainless steel and other metals, according to

The Wall Street Journal

.

Participants in the exchange include aluminum makers

Alcoa

(AA) - Get Report

,

Kaiser Aluminum

(KLU)

and

Reynolds Aluminum Supply

, a division of

Reynolds Metals

(RLM) - Get Report

; stainless steel manufacturers

Allegheny Technologies

(ATI) - Get Report

and

North American Stainless

; brass and copper producer

Olin

(OLN) - Get Report

; and distributors

Vincent Metals Goods/Atlas Ideal Metals

, a unit of Toronto's

Rio Algom

, and

Thyssen Inc. North America

, a division of Germany's

Thyssen Krupp

(TYEKF)

.

All the companies will be equal partners as they try to grab a slice of the $200 billion specialty market pie, giving metal trading sites

e-Steel.com

and

MetalSite.com

a run for their money.