If I have a long time stock with one brokerage can I purchase the same stock at another brokerage and then sell it using "last in first out" to avoid long term cap gains.

I want to buy shares of ATT to use as a place to keep funds temporarily but get better return than I do in a savings acct.  I already own ATT in a different brokerage account and have held it for many years.  I do not wish to sell it now.  How can I do this without the irs making me follow the FIFO rule?  I want to use the LIFO rule.