how to select multiple sheets in excel while making universe

hi,

i have a requirement to use same excel data from 2 sheets (like sheet 1 and sheet 2) to make a universe in Sap bo 4.0.

i am trying to select multiple sheets in drop down....it is not allowing me do so....Do we have any other option to solve these.

Is it possible to select data from 2 sheets at a time.Please help me in solving these issue

Thanks in Advance