It's possible , you have to configure the E1 controllers like that , that is each E1 interface coresponds to one E1 controller , configure 7 controllers for R2 signaling like
controller e1 slot/port
cas-group channel timeslots range type {r2-analog | r2-digital | r2-pulse} [dtmf | r2-compelled [ani] | r2-non-compelled [ani] | r2-semi-compelled [ani]]
cas-custom channel
and one with ISDN signaling
controller e1 slot/port
framing no-crc4
line code hdb3
pri-group timeslots 1-24
E1-R2 config link
http://www.cisco.com/en/US/products/sw/iosswrel/ps1826/products_feature_guide09186a00800dc5cf.html
